Vehicle headlight

ABSTRACT

A vehicle headlight (10) includes a light source unit (30) including a plurality of light emitting elements (35), a reflector (39) that scans light from the plurality of light emitting elements (35) to form a light distribution pattern (350), and a control unit (60). The control unit (60) controls the light source unit (30) such that the light amount of light emitted from some light emitting elements to a predetermined region (AR) overlapping a target object does not change and the light amount of light emitted from other some light emitting elements to the predetermined region (AR) overlapping the target object changes among the light emitting elements that emit light to the predetermined region (AR) overlapping the target object in the superimposition region (PA).

TECHNICAL FIELD

The present invention relates to a vehicle headlight.

BACKGROUND ART

As a vehicle headlight typified by an automotive headlight, a vehicleheadlight capable of changing a light distribution pattern of emittedlight is known. For example, Patent Literature 1 below describes avehicle headlight including a light source unit including a plurality oflight emitting elements and a reflector that repeats a periodic motion,and the reflector forms a predetermined light distribution pattern byreflecting and scanning light from the plurality of light emittingelements. Patent Literature 1 below describes changing a lightdistribution pattern of emitted light by adjusting emission of lightfrom the plurality of light emitting elements.

In addition, conventionally, there is known a vehicle headlight systemthat detects a light-emitting object that emits light by itself, such asa car ahead, and a retroreflective object that retroreflects light at apredetermined spreading angle without emitting light by itself, such asa road sign. Such a vehicle headlight system is disclosed in PatentLiterature 2. The vehicle headlight system disclosed in PatentLiterature 2 includes a headlight that alternately repeats lightirradiation and non-irradiation, and an imaging unit that captures animage of the front of the self-vehicle at the time of irradiation and atthe time of non-irradiation and generates an irradiation image and anon-irradiation image. In addition, the vehicle headlight systemincludes a detection unit that determines a high luminance portionlocated in the non-irradiation image as a light-emitting object, anddetermines a high luminance portion located in the irradiation image butnot located in the non-irradiation image as a retroreflective object.

-   [Patent Literature 1] WO 2019/073994 A-   [Patent Literature 2] JP 2011-110999 A

SUMMARY OF INVENTION

A vehicle headlight of the present invention includes: a light sourceunit configured to include a plurality of light emitting elements; areflector configured to repeat a periodic motion to reflect light fromthe plurality of light emitting elements and scan the light to form apredetermined light distribution pattern; and a control unit configuredto control the light source unit, in which the predetermined lightdistribution pattern includes a superimposition region where the lightfrom at least two of the light emitting elements is superimposed on eachother, and in a case where a signal indicating that a target objectlocated in front of a vehicle is detected is input from a detectiondevice, the control unit controls the light source unit such that alight amount of light emitted from some light emitting elements to apredetermined region overlapping the target object does not change and alight amount of light emitted from other some light emitting element tothe predetermined region overlapping the target object changes among thelight emitting elements emitting light to the predetermined regionoverlapping the target object in the superimposition region.

In the vehicle headlight, the light distribution pattern of the emittedlight changes according to the situation in front of the vehicle, andthe light amount of light emitted to the target object changes. Inaddition, in the vehicle headlight, even in a case where the targetobject is detected, the light amount of light emitted from some lightemitting elements to the predetermined region overlapping the targetobject does not change. Therefore, in the vehicle headlight, even whenthe light distribution pattern of the emitted light is changed, thelight from some light emitting elements is emitted to the target object.When the light irradiates the target object, the difficulty in visuallyrecognizing the target object can be suppressed and the driving can befacilitated as compared with the case where the light distributionpattern of the emitted light changes and the target object is notirradiated with the light. In addition, in the vehicle headlight, thenumber of light emitting elements that change the light amount of lightemitted is smaller than that in a case where the light amount of lightemitted from all the light emitting elements that emit light to thepredetermined region overlapping the target object is changed.Therefore, with the vehicle headlight, the control of the light sourceunit by the control unit can be simplified as compared with such a case.Note that, for example, in a case where the target object is detected bythe detection device and the target object is a human such as apedestrian, the light amount of light emitted to the human changes. Forexample, when the light amount of light emitted to the human increases,in the vehicle headlight, the human can be easily visually recognizedand the driving can be facilitated as compared with the case where thelight amount of light emitted to the human does not change. In addition,in a case where the target object is detected by the detection deviceand the target object is a retroreflective object such as a sign, thelight amount of light emitted to the retroreflective object changes. Ina case where the retroreflective object reflects the light from thevehicle headlight, the intensity of reflected light from theretroreflective object to the self-vehicle tends to increase as theintensity of light emitted to the retroreflective object increases. Forexample, when the light amount of light emitted to the retroreflectiveobject is reduced, the intensity of light to the retroreflective objectis suppressed and the intensity of reflected light can be suppressed ascompared with the case where the light amount of light emitted to theretroreflective object does not change. Therefore, in the vehicleheadlight, impartment of glare to the driver of the self-vehicle can besuppressed, and driving can be facilitated.

The width of the predetermined region in the left-right directionoverlapping the target object may change according to the distancebetween the vehicle and the target object.

From the viewpoint of the driver, the target object looks larger as thedistance between the vehicle and the target object is shorter.Therefore, with the above configuration, the light amount of lightemitted to the target object can be appropriately changed as comparedwith the case where the width of the predetermined region in theleft-right direction in which the light amount of emitted light changesdoes not change according to the distance between the vehicle and thetarget object.

In a case where the target object is a human, the control unit maycontrol the light source unit such that the light amount of lightemitted from the other some light emitting elements to the predeterminedregion overlapping the target object increases.

With such a configuration, the human can be easily visually recognizedand the driving can be facilitated as compared with the case where thelight amount of light emitted to the human such as a pedestrian does notchange.

In a case where the target object is a retroreflective object, thecontrol unit may control the light source unit such that the lightamount of light emitted from the other some light emitting elements tothe predetermined region overlapping the target object decreases.

With such a configuration, impartment of glare to the driver of theself-vehicle can be suppressed and the driving can be facilitated ascompared with the case where the light amount of light emitted to theretroreflective object does not change.

The control unit may control the light source unit such that the lightamount of light emitted from the other some light emitting elements tothe predetermined region overlapping the target object changes accordingto the distance between the vehicle and the target object.

With such a configuration, the light amount of light emitted to thetarget object changes according to the distance between the vehicle andthe target object. The driver tends to have difficulty in visuallyrecognizing the human as the distance between the vehicle and the humanis longer. Therefore, for example, the farther the distance between thevehicle and the human, the larger the light amount of light emitted tothe human. In this case, in the vehicle headlight, the human can beeasily visually recognized as compared with the case where the lightamount of light emitted to the human does not change according to thedistance between the vehicle and the human. In addition, in a case wherethe retroreflective object reflects the light from the vehicleheadlight, the intensity of reflected light from the retroreflectiveobject to the self-vehicle tends to increase as the distance between theself-vehicle and the retroreflective object is shorter. Therefore, forexample, the closer the distance between the vehicle and theretroreflective object, the smaller the light amount of light emitted tothe retroreflective object. In this case, in the vehicle headlight,impartment of glare to the driver of the self-vehicle can be suppressedas compared with the case where the light amount of light emitted to theretroreflective object does not change according to the distance betweenthe vehicle and the retroreflective object.

In a case where the target object is a retroreflective object and thecontrol unit controls the light source unit such that the light amountof light emitted from the other some light emitting elements to thepredetermined region overlapping the target object is reduced, thecontrol unit may control the light source unit such that the lightamount of light emitted from the other some light emitting elements tothe predetermined region overlapping the target object is reducedaccording to the intensity of light from the target object toward thevehicle.

With such a configuration, the impartment of glare to the driver of theself-vehicle can be appropriately suppressed.

Alternatively, the control unit may control the light source unit suchthat the light amount of light emitted from the other some lightemitting elements to the predetermined region overlapping the targetobject decreases as the angle formed by a traveling direction of thevehicle and the direction from the vehicle toward the target objectdecreases.

In general, in a light distribution pattern of light emitted from avehicle headlight, the intensity of light tends to increase to a centerside. Therefore, as the angle between the traveling direction of thevehicle and the direction from the vehicle toward the target objectdecreases, the intensity of light emitted to the target object tends toincrease. Therefore, for example, by controlling the light source unitsuch that the smaller the angle is, the smaller the light amount oflight emitted to the predetermined region overlapping theretroreflective object, which is a target object, the impartment ofglare to the driver of the self-vehicle can be appropriately suppressed.

When the control unit controls the light source unit such that the lightamount of light emitted from the other some light emitting elements tothe predetermined region overlapping the target object changes accordingto the distance between the vehicle and the target object or theintensity of light from the retroreflective object toward the vehicle,the control unit may change the number of the other some light emittingelements to change the light amount of light emitted from the other somelight emitting elements to the predetermined region overlapping thetarget object in a case where the number of the light emitting elementsthat emit light to the predetermined region overlapping the targetobject is three or more.

The reflector may be a rotary reflector that reflects the light from theplurality of light emitting elements while rotating.

A determination unit that determines whether the target object satisfiesa predetermined requirement that a light amount of reflected light fromthe target object is equal to or more than a predetermined value in acase where a signal indicating a state of the target object is inputfrom the detection device is further provided, in which each scanningregion through which a spot of light from each light emitting elementscanned by the reflector in the predetermined light distribution patternpasses is divided into a pair of end portions that includes an end in ascanning direction and is equal to or more than a width of the spot inthe scanning direction and a center portion sandwiched by the pair ofend portions, each of the scanning regions is arranged to be displacedin the scanning direction, a part of the center portion of each of thescanning regions overlaps a part of center portions of all the otherscanning regions, and the end portion of each of the scanning regionsdoes not overlap the end portion of all the other scanning regions, in acase where the predetermined region moves in the scanning direction froma first state in which the predetermined region is located in the centerportion in all the scanning regions corresponding to the other somelight emitting elements to a second state in which the predeterminedregion overlaps the end portion in at least one of the scanning regionscorresponding to the other some light emitting elements and is locatedin the center portion in the scanning region corresponding to at leastone of the light emitting elements among the some light emittingelements, the control unit may control the light source unit such thatthe light amount emitted to the predetermined region from the lightemitting element corresponding to the scanning region in which thepredetermined region overlaps the end portion in the other some lightemitting elements returns to the light amount emitted to thepredetermined region in a case where the determination unit does notdetermine that the target object satisfies the predeterminedrequirement, and the light amount emitted to the predetermined region inthe second state becomes the light amount in the first state by changingthe light amount emitted to the predetermined region from at least oneof the light emitting elements corresponding to the scanning region inwhich the predetermined region is located in the center portion amongsome light emitting elements.

In the vehicle headlight, as described above, a light distributionpattern is formed by periodic scanning of light from the plurality oflight emitting elements. In such a vehicle headlight, for example, whenthe predetermined region overlapping the target object is located in thevicinity of an end in the scanning direction of the scanning regionthrough which the spot of light from the light emitting element passes,the distance between this end and the predetermined region may benarrower than the width of the spot in the scanning direction. By theway, the shortest length that allows light scanning is the width of thespot in the scanning direction. Therefore, in the case as describedabove, the light amount emitted to the predetermined region cannot bechanged without changing the light amount emitted between the end andthe predetermined region. Therefore, the light amount emitted betweenthe above-described end and the predetermined region is also changedtogether with the predetermined region, and the region where the lightamount is changed may suddenly become large, and the driver may feel asense of discomfort. On the other hand, in this vehicle headlight, eachscanning region corresponding to each light emitting element is dividedinto a pair of end portions and a center portion, and the width of theend portion is equal to or more than the width of the spot. Then, in thecase of the second state in which the end portion of the scanning regioncorresponding to the light emitting element that emits the light inwhich the light amount of light emitted to the predetermined region ischanged overlaps the predetermined region, the control unit controls thelight source unit such that the light amount of light emitted from thelight emitting element returns to the light amount emitted to thepredetermined region in a case where the determination unit does notdetermine that the target object satisfies the predeterminedrequirement. Therefore, with the vehicle headlight, the distance betweenthe predetermined region and the end of the scanning regioncorresponding to the light emitting element in which the light amount oflight emitted to the predetermined region is changed can be preventedfrom being less than the width of the condensing spot in the scanningdirection. In addition, in this case, the control unit controls thelight source unit such that the light amount emitted to thepredetermined region in the second state becomes the light amount in thefirst state by changing the light amount emitted to the predeterminedregion from the light emitting element in which the predetermined regionis located in the center portion of the scanning region among the lightemitting elements that emit light in which the light amount of lightemitted to the predetermined region is not changed. Therefore, with thevehicle headlight, a change in the light amount emitted to the vicinityof the predetermined region can be suppressed, the brightness of thepredetermined region can be prevented from changing, and the driver canbe suppressed from feeling a sense of discomfort.

The predetermined region in the second state may be located in thecenter portion of the scanning region corresponding to two or more ofthe light emitting elements among some light emitting elements, and inthe case of changing from the first state to the second state, the lightamount emitted to the predetermined region from the light emittingelement corresponding to the scanning region in which the distancebetween the center of the center portion in the scanning direction andthe predetermined region is the shortest among the two or more of thelight emitting elements among some light emitting elements may change.

In this vehicle headlight, the light amount of light emitted from thelight emitting element corresponding to the scanning region in which thedistance between the center of the center portion and the predeterminedregion is the shortest to the predetermined region changes. Therefore,even when the predetermined region further moves to one side or theother side in the scanning direction, the end portion of the scanningregion corresponding to the light emitting element in which the lightamount of light emitted to the predetermined region is changed in thecase of changing from the first state to the second state and thepredetermined region can be made less likely to overlap each other.Accordingly, with the vehicle headlight, it is possible to suppress anincrease in the number of times the control unit controls the lightsource unit as described above.

In addition, the state that satisfies the predetermined requirement maybe a state in which the distance between the target object and thevehicle is less than the predetermined distance.

In addition, the state that satisfies the predetermined requirement maybe a state in which the apparent size of the target object is equal toor more than a predetermined value.

A vehicle headlight of the present invention includes: a plurality oflight source units; a reflector configured to repeat a periodic motionto reflect light from the plurality of light source units and scan thelight; and a control unit configured to control the plurality of lightsource units, in which the reflector reflects the light from theplurality of light source units such that a first light distributionpattern formed by scanning of light from some light source units amongthe plurality of light source units and a second light distributionpattern formed by scanning of light from other some light source unitsamong the plurality of light source units partially overlap each otherin an up-down direction of a vehicle, and in a case where a signalindicating that a retroreflective object located in front of the vehicleis detected is input from a detection device, the control unit controlsthe plurality of light source units such that the light amount of lightemitted to a predetermined region overlapping the retroreflective objectin one of the first light distribution pattern and the second lightdistribution pattern is reduced as compared with a case where a signalindicating that the retroreflective object is not detected is input fromthe detection device.

In a case where the retroreflective object reflects the light, theintensity of reflected light from the retroreflective object to theself-vehicle tends to increase as the intensity of light from the lightsource units to the retroreflective object increases. Here, a case wherethe signal indicating that the retroreflective object is detected isinput to the control unit from the detection device is compared with thecase where the signal indicating that the retroreflective object is notdetected is not input to the control unit from the detection device. Ina case where the signal indicating that the retroreflective object isdetected is input to the control unit, as compared with the case wherethe signal indicating that the retroreflective object is not detected isnot input to the control unit, the light amount of light emitted to thepredetermined region overlapping the retroreflective object in one ofthe first light distribution pattern and the second light distributionpattern is reduced. The light is a part of the light forming one of thefirst light distribution pattern and the second light distributionpattern. When the light amount of light decreases, the intensity oflight to the retroreflective object is suppressed, and the intensity ofthe reflected light can be suppressed, as compared with the case wherethe light amount does not decrease. Thus, even when the reflected lighttravels to the self-vehicle, impartment of glare to the driver of theself-vehicle can be suppressed. Accordingly, with the vehicle headlight,a reduction in driver's visibility can be suppressed.

In addition, a determination unit that determines whether theretroreflective object satisfies the predetermined requirement that thelight amount of light reflected from the retroreflective object is equalto or more than the predetermined value in a case where the signalindicating the state of the retroreflective object is input from thedetection device is further provided, the light source unit that emitslight emitted to the predetermined region includes a plurality of lightemitting elements, and the control unit may control the light sourceunit such that each of the light amount of the light from some lightemitting elements among the plurality of light emitting elements and thelight amount of the light from other some light emitting elements amongthe plurality of light emitting elements is reduced in a case where thedetermination unit determines that the retroreflective object satisfiesthe predetermined requirement as compared with the case where thedetermination unit determines that the retroreflective object does notsatisfy the predetermined requirement.

With the vehicle headlight, in the state in which the retroreflectiveobject satisfies the predetermined requirement, the irradiation of theretroreflective object with light is suppressed, and the intensity ofthe reflected light can be further suppressed as compared with the statein which the retroreflective object does not satisfy the predeterminedrequirement. Accordingly, with the vehicle headlight, a reduction indriver's visibility can be further suppressed.

In addition, a determination unit that determines whether theretroreflective object satisfies the predetermined requirement that thelight amount of light reflected from the retroreflective object is equalto or more than the predetermined value in a case where the signalindicating the state of the retroreflective object is input from thedetection device is further provided, the light source unit that emitslight emitted to the predetermined region includes a plurality of lightemitting elements, and the control unit may control the light sourceunit such that the light amount of the light from some light emittingelements among the plurality of light emitting elements is reduced andthe light amount of the light from other some light emitting elementsamong the plurality of light emitting elements becomes the same in acase where the determination unit determines that the retroreflectiveobject satisfies the predetermined requirement as compared with the casewhere the determination unit determines that the retroreflective objectdoes not satisfy the predetermined requirement.

In a case where the retroreflective object satisfies the predeterminedrequirement and a case where the retroreflective object does not satisfythe predetermined requirement, when the light amount of light from othersome light emitting element is the same, the control unit can performthe same control on the other some light emitting element in both cases.For example, even when the state is switched from the case where theretroreflective object does not satisfy the predetermined requirement tothe case where the retroreflective object satisfies the predeterminedrequirement, the control unit may not need to change the amount of powersupplied to the other some light emitting elements. Accordingly, thecontrol unit can easily control other some light emitting elements ascompared with the case where the light amount of light from other somelight emitting elements changes in a case where the retroreflectiveobject satisfies the predetermined requirement and a case where theretroreflective object does not satisfy the predetermined requirement.

In addition, the state that satisfies the predetermined requirement maybe a state in which the distance between the retroreflective object andthe vehicle is less than the predetermined distance.

In addition, the state that satisfies the predetermined requirement maybe a state in which the apparent size of the retroreflective object isequal to or more than a predetermined value.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan diagram conceptually illustrating a vehicle.

FIG. 2 is a diagram schematically illustrating one lighting tool of afirst embodiment.

FIG. 3 is a diagram illustrating a layout of light emitting elements ofa light source unit of the first embodiment.

FIG. 4 is a diagram illustrating a scanning region through which acondensing spot of light from each light emitting element of the firstembodiment passes.

FIG. 5 is a diagram illustrating a scanning region of the firstembodiment.

FIG. 6 is a time chart illustrating a turn-on/turn-off state of thelight emitting element of the first embodiment.

FIG. 7 is a flowchart illustrating an operation of a vehicle headlight.

FIG. 8 is a diagram describing scanning of a condensing spot in Step S4.

FIG. 9 is a diagram illustrating a predetermined light distributionpattern in Step S4.

FIG. 10 is a diagram describing scanning of a condensing spot in StepS5.

FIG. 11 is a diagram illustrating a specific light distribution patternin Step S5.

FIG. 12 is a diagram describing a scanning region in a modification ofthe first embodiment.

FIG. 13 is a diagram describing an example of setting of a light amountchange region in Step S5 in the modification of the first embodiment.

FIG. 14 is a diagram describing another example of setting of the lightamount change region in Step S5 in the modification of the firstembodiment.

FIG. 15 is a diagram schematically illustrating one lighting tool of asecond embodiment.

FIG. 16 is a diagram illustrating a layout of light emitting elements ofa plurality of light source units of the second embodiment.

FIG. 17 is a diagram illustrating a scanning region through which acondensing spot of light from each light emitting element of the secondembodiment passes.

FIG. 18 is a diagram illustrating a scanning region of the secondembodiment.

FIG. 19 is a diagram describing scanning of a condensing spot in StepS4.

FIG. 20 is a diagram illustrating a first light distribution pattern anda second light distribution pattern in Step S4.

FIG. 21 is a diagram describing scanning of a condensing spot in StepS5.

FIG. 22 is a diagram illustrating a first light distribution pattern anda second light distribution pattern in Step S5.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of a vehicle headlight according to the presentinvention will be described below in detail with reference to thedrawings. The embodiments illustrated below are for facilitating theunderstanding of the present invention, and are not for limiting theinterpretation of the present invention. The present invention can bechanged or modified without departing from the spirit. In addition, inthe present invention, components in the following exemplary embodimentsmay be appropriately combined. Note that, for easy understanding, someparts may be exaggerated in each drawing.

(First Embodiment)

A first embodiment as a first aspect of the present invention will bedescribed. FIG. 1 is a plan diagram conceptually illustrating a vehicle100. As illustrated in FIG. 1 , the vehicle 100 includes a vehicleheadlight 10 and a detection device 110.

The vehicle headlight 10 of the present embodiment is a headlight for anautomobile. The vehicle headlight 10 mainly includes a pair of lightingtools 20 arranged on the left and right of a front portion of thevehicle 100, a determination unit 50, a control unit 60, and a recordingunit 70. Note that, in the present specification, “right” means theright side in the traveling direction of the vehicle 100, and “left”means the left side in the traveling direction of the vehicle 100.

The pair of lighting tools 20 has a substantially symmetrical shape inthe left-right direction of the vehicle 100. The pair of lighting tools20 of the present embodiment emits a low beam or a high beam to thefront of the vehicle 100. The configuration of one lighting tool 20 a ofthe pair of lighting tools 20 is the same as the configuration of theother lighting tool 20 b of the pair of lighting tools 20 except thatthe shape is substantially symmetrical. Therefore, the configuration ofeach of the lighting tools 20 a and 20 b will be described below usingthe lighting tool 20 a.

FIG. 2 is a diagram schematically illustrating the lighting tool 20 a ofthe first embodiment illustrated in FIG. 1 . As illustrated in FIG. 2 ,the lighting tool 20 a includes, as main configurations, a light sourceunit 30, a reflector 39, a drive unit 41, and a projection lens 43.

The light source unit 30 includes a plurality of light emitting elements35 mounted on a circuit board 33. The plurality of light emittingelements 35 is arranged in a row along a predetermined direction. As thelight emitting element 35, for example, a light emitting diode (LED) orthe like is used. FIG. 2 illustrates the light source unit 30 includingfive light emitting elements 35. Note that the number of the lightemitting elements 35 in the light source unit 30 is not particularlylimited as long as it is two or more.

Power is supplied to each light emitting element 35 via the circuitboard 33. The light amount of light emitted from each light emittingelement 35 is adjusted by adjusting the power supplied to each lightemitting element 35. The light is emitted toward the reflector 39.

Examples of the reflector 39 of the present embodiment include a rotaryreflector. The reflector 39 is fixed to an output shaft, which is notillustrated, of the drive unit 41, and rotates about a rotation axis,which is not illustrated, of the drive unit 41 passing through thecenter of the output shaft by a rotational force from the drive unit 41.The reflector 39 rotates to repeat a periodic motion. Examples of thedrive unit 41 include a motor having an encoder, which is notillustrated, that detects the rotational position of the output shaftfrom the reference position. The encoder outputs a signal indicatingrotational position information such as the detected rotational positionof the output shaft to the control unit 60. Note that the lighting tool20 a may include a sensor that detects rotational position informationsuch as the rotational position of the reflector 39 from the referenceposition instead of the encoder. In this case, the sensor outputs asignal indicating the rotational position information to the controlunit 60. The reflector 39 includes two reflection blades 39 a thatreflect the light from the light source unit 30 toward the projectionlens 43.

The projection lens 43 of the present embodiment is an asphericalplano-convex lens. In the projection lens 43, an incident surface whichis a surface on a side on which the light reflected by the reflectionblades 39 a of the reflector 39 is incident is formed in a planar shape,and an emission surface which is a surface on a side from which theincident light is emitted is formed in a convex shape bulging in anemission direction.

In the present embodiment, the plurality of light emitting elements 35of the light source unit 30 emits light toward the reflector 39, and thereflector 39 rotates. Thus, the reflector 39 repeats the rotationalmotion that is a periodic motion to reflect the light from the pluralityof light emitting elements 35 toward the projection lens 43 side, andscans the light in the left-right direction of the vehicle 100. Whenthis light passes through the projection lens 43, is emitted to thefront of the vehicle 100, and scanned in the left-right direction of thevehicle 100, a predetermined light distribution pattern 350 is formed ona vertical plane 200 in front of the vehicle 100. Accordingly, thereflector 39 repeats the periodic motion to reflect the light from theplurality of light emitting elements 35 and periodically scan the lightto form the predetermined light distribution pattern 350. Thepredetermined light distribution pattern 350 illustrated in FIG. 2indicates a light distribution pattern of a high beam having arectangular shape horizontally long in the left-right direction of thevehicle 100. In the present embodiment, the shape of the reflectingsurface of the reflection blades 39 a that reflect the light from theplurality of light emitting elements 35, the positions of the pluralityof light emitting elements 35 with respect to the reflection blades 39a, and the like are adjusted so as to form the predetermined lightdistribution pattern 350. Although details will be described below, thepredetermined light distribution pattern 350 to be formed can be changedby controlling the emission of light from the plurality of lightemitting elements 35.

Here, referring back to FIG. 1 , the description of the vehicle will becontinued.

The control unit 60 determines whether a control signal from a lightswitch, which is not illustrated, mounted on the vehicle 100 is input.The control signal is a signal instructing start of emission of lightfrom the light source unit 30 of each of the lighting tool 20 a and thelighting tool 20 b. In a case where the control signal is input to thecontrol unit 60, the control unit 60 drives the light source unit 30 anddrives the drive unit 41. In a case where the control signal is notinput to the control unit 60, the control unit 60 stops the driving ofthe light source unit 30 and stops the driving of the drive unit 41.

The control unit 60 can use, for example, an integrated circuit such asa microcontroller, an integrated circuit (IC), a large-scale integratedcircuit (LSI), or an application specific integrated circuit (ASIC), ora numerical control (NC) device. In addition, when the NC device isused, the control unit 60 may use a machine learning device or may notuse a machine learning device.

The detection device 110 detects a target object located in front of thevehicle 100. Examples of the target object detected by the detectiondevice 110 include a retroreflective object and an object other than theretroreflective object. The retroreflective object of the presentembodiment is an object that does not emit light by itself andretroreflects light emitted to the retroreflective object at apredetermined spreading angle. Examples of such a retroreflective objectinclude a road sign installed in the vicinity of the road. In addition,examples of the object other than the retroreflective object include avehicle such as a preceding vehicle or an oncoming vehicle, and a humansuch as a pedestrian.

As a configuration of the detection device 110, the detection device 110mainly includes, for example, a camera, an image processing unit, adetection unit, and the like, which are not illustrated. The camera isattached to the front portion of the vehicle 100 and captures an imageof the front of the vehicle 100. The captured image captured by thecamera includes at least a part of a region irradiated with lightemitted from the pair of lighting tools 20. The image processing unitperforms image processing on a captured image captured by the camera.When detecting the target object, the detection unit outputs a signalindicating that the target object is detected to the control unit 60 viathe determination unit 50. Note that the detection unit may directlyoutput the signal to the control unit 60. In addition, the detectionunit detects the state of the target object from the informationsubjected to the image processing by the image processing unit. Examplesof the state of the target object include the presence of the targetobject, the presence position of the target object in the capturedimage, the type of the target object, and the ratio of the target objectin the captured image. When detecting a target object located in frontof the vehicle 100, the detection device 110 outputs a signal indicatingthe state of the target object to the determination unit 50 and outputsthe captured image to the recording unit 70. The detection device 110identifies and detects a retroreflective object and a human as targetobjects as described below. In addition, when no target object ispresent in front of the vehicle 100 and the target object is notdetected, the detection device 110 outputs a signal indicating that thetarget object is not detected to the determination unit 50 and outputsthe captured image to the recording unit 70. The signal is also a signalindicating that the target object is not present. Note that thedetection device 110 may not output the signal in a case where thetarget object is not detected. In addition, the target object detectedby the detection device 110, the number of types of target objects, andthe configuration of the detection device 110 are not particularlylimited. Examples of the configuration of the image processing unit andthe configuration of the detection unit include the same configurationas the control unit 60. In addition, the control unit 60 and at leastone of the image processing unit and the detection unit of the detectiondevice 110 may be integrally configured, and the control unit 60 mayalso serve as at least one of the image processing unit and thedetection unit.

Next, an example of detection of the presence of a retroreflectiveobject from the captured image will be described. Note that theretroreflective object will be described as a road sign. The recordingunit 70 records image data of each road sign in advance. When the targetobject shown in the captured image corresponds to the image data of theroad sign recorded in the recording unit 70, the detection unit detectsthe target object as a retroreflective object. As another example ofdetection, generally, the shape of a road sign is a circle, a rectangle,or a triangle, and the road sign has a combination of colors such asred, white, blue, yellow, black, and green. The detection unit maydetect the target object as the retroreflective object as long as theouter shape of the target object shown in the captured image captured bythe camera is any of a circle, a rectangle, and a triangle, and thecolor inside the outer shape of the target object is a combination ofthe above colors. The above two examples of detection may be combined.In addition, when the retroreflective object is a delineator, the lightreflected from the delineator is, for example, orange. When the lightfrom the target object shown in the captured image captured by thecamera is orange, the detection unit may detect the target object as aretroreflective object. Note that the detection of the retroreflectiveobject by the detection unit is not limited to the above.

Next, an example of detection of the presence of a human from thecaptured image will be described. The detection unit detects a targetobject as a human when authenticating the face of the human shown in thecaptured image. Alternatively, the detection unit may include a humansensor that detects infrared rays near body temperature emitted from ahuman. In a case where the human sensor detects infrared rays andinfrared rays are shown in the captured image, the detection unit maydetect a target object that is shown in the captured image and emitsinfrared rays as a human. Note that the detection of the human by thedetection unit is not limited to the above.

On the basis of a signal indicating the state of the target object fromthe detection device 110 that detects the target object located in frontof the vehicle 100, the determination unit 50 determines whether thetarget object satisfies a predetermined requirement that the lightamount of the reflected light from the target object to the self-vehicleis equal to or more than a predetermined value. The state that thepredetermined requirement is satisfied indicates, for example, a statein which the distance between the target object and the vehicle 100 isless than the predetermined distance. The predetermined distance is, forexample, 30 m. The numerical value of the distance is recorded in therecording unit 70 as a threshold value, and may be appropriatelychangeable according to the traveling status of the vehicle 100 such asdaytime and nighttime, the type of target object, and the like. Inaddition, the numerical value of the distance may be set for each typeof the target object. For example, the determination unit 50 mainlyincludes a calculation unit and a determination main unit. Thecalculation unit calculates the distance between the target object andthe vehicle 100 on the basis of the above ratio in the state of thetarget object from the detection device 110. A signal indicating thecalculated distance is output to the determination main unit. Thedetermination main unit reads a predetermined distance, which is athreshold value, from the recording unit 70, compares the calculateddistance with the predetermined distance, and determines whether thecalculated distance is larger than the predetermined distance. When thecalculated distance is equal to or more than the predetermined distance,the determination main unit determines that the target object does notsatisfy the predetermined requirement. In addition, when the calculateddistance is less than the predetermined distance, the determination mainunit determines that the target object satisfies the predeterminedrequirement. Then, when the determination main unit determines that thetarget object satisfies the predetermined requirement, the determinationunit 50 outputs a signal indicating the state of the target object suchas the distance calculated by the calculation unit, the presenceposition of the target object in the captured image, and the type of thetarget object to the control unit 60. Examples of the configuration ofthe determination unit 50 include the same configuration as the controlunit 60. Note that the control unit 60 and the determination unit 50 maybe integrally configured, and the control unit 60 may also serve as thedetermination unit 50.

The recording unit 70 records the captured image output from thedetection device 110 and the predetermined distance, which is thethreshold value described above, in the determination unit 50. Examplesof the recording unit 70 include a semiconductor memory such as ROM anda magnetic disk.

FIGS. 3 and 4 are diagrams describing formation of the predeterminedlight distribution pattern 350.

FIG. 3 is a diagram illustrating a layout of light emitting elements35-1 to 35-5 of the light source unit 30 of the present embodiment. Asdescribed above, the light source unit 30 includes the five lightemitting elements 35-1 to 35-5.

FIG. 4 is a diagram illustrating scanning regions SR1 to SR5 throughwhich condensing spots of light pass when the light from the lightemitting elements 35-1 to 35-5 are scanned by the reflector 39 to formthe predetermined light distribution pattern 350. The condensing spot isa spot formed by the light from each of the light emitting elements 35-1to 35-5, and is a spot projected in front of the vehicle 100. In FIG. 4, H represents a horizontal line along the left-right direction of thevehicle 100, and V represents a vertical line along the up-downdirection of the vehicle 100. A scanning region SR1 of the presentembodiment indicates a region through which a condensing spot formed bylight from an i-th (1≤i≤5) light emitting element 35-i passes. Thescanning regions SR1 to SR5 have a rectangular shape horizontally longin the left-right direction of the vehicle 100 and have substantiallythe same size. The positions of the scanning regions SR1 to SR5 in theup-down direction are substantially the same, and the positions in theleft-right direction are different. Accordingly, the scanning regionsSR1 to SR5 are arranged to be displaced from each other in theleft-right direction such that a part of each of the scanning regionsSR1 to SR5 overlaps a part of another scanning region. Note that, inFIG. 4 , the scanning regions SR1 to SR5 are illustrated to be displacedin the up-down direction for easy understanding. The outer shape of theset of scanning regions SR1 to SR5 corresponds to the outer shape of thepredetermined light distribution pattern 350 illustrated in FIG. 2 .

In the scanning regions SR1 to SR5, the scanning region SR1 is locatedon the leftmost side, and the scanning regions SR1 to SR5 are arrangedto be gradually displaced to the right in the order of the scanningregions SR1 to SR5. Accordingly, the center of the scanning region SR2in the left-right direction is located on the right side of the centerof the scanning region SR1 in the left-right direction, and a part ofthe scanning region SR2 and a part of the scanning region SR1 overlapeach other. In addition, the center of the scanning region SR3 in theleft-right direction is located on the right side of the center of thescanning region SR2 in the left-right direction, and a part of thescanning region SR3 and a part of the scanning regions SR1 to SR2overlap each other. The center of the scanning region SR4 in theleft-right direction is located on the right side of the center of thescanning region SR3 in the left-right direction, and a part of thescanning region SR4 and a part of the scanning regions SR1 to SR3overlap each other. The center of the scanning region SR5 in theleft-right direction is located on the right side of the center of thescanning region SR4 in the left-right direction, and a part of thescanning region SR5 and a part of the scanning regions SR1 to SR4overlap each other.

A center region CA is located at a center portion of the set of the setscanning regions SR1 to SR5 in the left-right direction. In the centerregion CA, parts of the five scanning regions SR1 to SR5 overlap eachother, and the center region CA can be irradiated with light from thefive light emitting elements 35-1 to 35-5. In a first left region LS1located on the left side of the center region CA, parts of the fourscanning regions SR1 to SR4 overlap each other, and in a first rightregion RS1 located on the right side of the center region CA, parts ofthe four scanning regions SR2 to SR5 overlap each other. In a secondleft region LS2 located on the left side of the first left region LS1,parts of the three scanning regions SR1 to SR3 overlap each other, andin a second right region RS2 located on the right side of the firstright region RS1, parts of the three scanning regions SR3 to SR5 overlapeach other. In a third left region LS3 located on the left side of thesecond left region LS2, parts of the two scanning regions SR1 and SR2overlap each other, and in a third right region RS3 located on the rightside of the second right region RS2, parts of the two scanning regionsSR4 and SR5 overlap each other. A fourth left region LS4 located on theleft side of the third left region LS3 includes a part of the scanningregion SR1, and a fourth right region RS4 located on the right side ofthe third right region RS3 includes a part of the scanning region SR5.Therefore, the first left region LS1 and the first right region RS1 canbe irradiated with the light from the four light emitting elements, andthe second left region LS2 and the second right region RS2 can beirradiated with the light from the three light emitting elements. Inaddition, the third left region LS3 and the third right region RS3 canbe irradiated with the light from the two light emitting elements, andthe fourth left region LS4 and the fourth right region RS4 can beirradiated with the light from the one light emitting element.

FIGS. 5 and 6 are diagrams describing control of the light emittingelement 35-i in the scanning region SR1. FIG. 5 is a diagramillustrating the scanning region SR1. In the scanning region SR1illustrated in FIG. 5 , a non-hatched range indicates a light amountchange region 311, and a hatched range indicates a light amountnon-change region 313. The light amount non-change region 313 is aregion where the light amount of light from the light emitting element35-i is substantially a predetermined amount. On the other hand, thelight amount change region 311 is a region in which the light amount oflight from the light emitting element 35-i is different from the lightamount of light emitted to the light amount non-change region 313. FIG.6 is a time chart illustrating the light amount of light emitted fromthe light emitting element 35-i. TS illustrated in FIG. 6 indicates ascanning period.

SCi illustrated in FIG. 5 indicates a position of a condensing spot oflight from the light emitting element 35-i at a certain time. It isassumed that the condensing spot SCi is scanned from the left to theright in the drawing. It is assumed that a left end LE of the condensingspot SCi is located at the left end of the scanning region SR1 at acertain time t0. The control unit 60 grasps the position of thecondensing spot SCi in the scanning region SR1 on the basis of therotational position information from the drive unit 41, and controls theluminance of the light emitting element 35-i in synchronization with therotational position information. Note that, in FIG. 5 , the size of thecondensing spot SCi with respect to the scanning region SR1 is largerthan the actual size for easy understanding.

In the light amount non-change region 313, the control unit 60 controlsthe luminance of the light emitting element 35-i such that the lightamount of light emitted from the light emitting element 35-icorresponding to the condensing spot SCi becomes a first predeterminedvalue during a period in which the condensing spot SCi passes throughthe light amount non-change region 313. The first predetermined valueindicates a value of the light amount of light emitted from the lightemitting element 35-i in the light amount non-change region 313. Inaddition, the first predetermined value is, for example, 80% or the likeof the maximum value of the light amount of light emitted from the lightemitting element 35-i.

In addition, in the light amount change region 311, the control unit 60controls the luminance of the light emitting element 35-i such that thelight amount of light emitted from the light emitting element 35-icorresponding to the condensing spot SCi becomes a second predeterminedvalue during a period in which the condensing spot SCi passes throughthe light amount change region 311. Specifically, as illustrated inFIGS. 5 and 6 , the control unit 60 controls the light amount of lightemitted from the light emitting element 35-i to the second predeterminedvalue at timing to at which a right end RE of the condensing spot SCireaches the light amount change region 311. In addition, the controlunit 60 controls the light amount of light emitted from the lightemitting element 35-i to the first predetermined value at timing tB atwhich the left end LE of the condensing spot SCi reaches the right endof the light amount change region 311. The second predetermined valueindicates a value of the light amount of light emitted from the lightemitting element 35-i in the light amount change region 311. The secondpredetermined value is a value different from the first predeterminedvalue. FIG. 6 illustrates an example in which the second predeterminedvalue is lower than the first predetermined value. In a case where thesecond predetermined value is lower than the first predetermined value,the second predetermined value is, for example, 30% or zero or the likeof the maximum value of the light amount of light emitted from the lightemitting element 35-i. In addition, the second predetermined value maybe made higher than the first predetermined value, and in this case, thesecond predetermined value is, for example, a maximum value of the lightamount of light emitted from the light emitting element 35-i. When thesecond predetermined value is zero, the light from the light emittingelement 35-i is turned off.

FIG. 7 is a flowchart illustrating an operation of the vehicle headlight10 in the present embodiment. As illustrated in FIG. 7 , the flowchartof the present embodiment includes Steps S1 to S5.

(Step S1)

The detection device 110 captures an image of the front of the vehicle100 with a camera. When detecting a target object located in front ofthe vehicle 100 from the captured image, the detection device 110outputs a signal indicating that the target object is detected to thecontrol unit 60 via the determination unit 50, and outputs a signalindicating the state of the target object to the determination unit 50.In addition, when not detecting a target object located in front of thevehicle 100 from the captured image, the detection device 110 outputs asignal indicating that the target object is not detected to thedetermination unit 50. In the present embodiment, the detection device110 identifies and detects a retroreflective object and a human astarget objects. When the signal is input, the processing proceeds toStep S2.

(Step S2)

In the present step, the control unit 60 determines whether to emit thelight on the basis of the control signal from the light switch. In acase where the control signal is not input to the control unit 60, thecontrol unit 60 stops the driving of the plurality of light source units30 and stops the driving of the drive unit 41, and the light is notemitted, and the processing returns to Step S1. In addition, in a casewhere the control signal is input to the control unit 60, the light isemitted, and the processing proceeds to Step S3.

(Step S3)

In the present step, the determination unit 50 determines whether thetarget object satisfies a predetermined requirement on the basis of thesignal indicating the state of the target object from the detectiondevice 110. In a case where the determination unit 50 determines thatthe target object does not satisfy the predetermined requirement, theprocessing proceeds to Step S4. In addition, in a case where the signalindicating that the target object is not detected is input to thedetermination unit 50, it is determined that the target object does notsatisfy the predetermined requirement, and the processing proceeds toStep S4. On the other hand, in a case where the determination unit 50determines that the target object satisfies the predeterminedrequirement, the determination unit 50 outputs a signal indicating thestate of the target object such as the distance between the targetobject and the vehicle 100 calculated by the calculation unit, thepresence position of the target object in the captured image, and thetype of the target object to the control unit 60. When the determinationunit 50 outputs the signal, the processing proceeds to Step S5.Hereinafter, the state that the predetermined requirement is satisfiedwill be described as an example in which the distance between the targetobject and the vehicle 100 is less than a predetermined distance. Inaddition, in the following description, it is assumed that the targetobject is located diagonally forward left of the vehicle 100.

(Step S4)

In the present step, as described in Step S3, the retroreflective objectas the target object is detected by the detection device 110, and thedistance between the retroreflective object and the vehicle 100 is equalto or more than the predetermined distance, or the target object is notdetected by the detection device 110. In this case, the control unit 60controls the driving of the light source unit 30 and also controls thedriving of the drive unit 41. FIG. 8 is a diagram describing scanning ofcondensing spots SC1 to SC5 in the present step. FIG. 9 is a diagramillustrating a predetermined light distribution pattern 350 formed whenthe distance between the retroreflective object 401 as a target objectand the vehicle 100 is equal to or more than a predetermined distance.Note that the predetermined light distribution pattern 350 illustratedin FIG. 9 is the same as the predetermined light distribution pattern350 illustrated in FIG. 2 .

Here, first, scanning of the condensing spots SC1 to SC5 in the presentstep will be described with reference to FIG. 8 . In FIG. 8 , theplurality of scanning regions SR1 to SR5 is displaced and arranged foreasy viewing. The condensing spots SC1 to SC5 scan the scanning regionsSR1 to SR5 from the left to the right in the drawing. When the distancebetween the target object and the vehicle 100 is equal to or more thanthe predetermined distance and when the target object is not detected bythe detection device 110, the control unit 60 sets each of the scanningregions SR1 to SR5 as the light amount non-change region 313. Next, thecontrol unit 60 controls the light emitting elements 35-1 to 35-5 suchthat the light amount of light emitted from the light emitting elements35-1 to 35-5 corresponding to the condensing spots SC1 to SC5 becomesthe first predetermined value.

When the light emitting elements 35-1 to 35-5 controlled as describedabove emit light, the light is reflected toward the projection lens 43by the reflector 39 rotated by the drive unit 41. In addition, the lightpasses through the projection lens 43, is emitted to the front of thevehicle 100, and scans in the left-right direction of the vehicle 100.By this light scanning, the predetermined light distribution pattern 350is formed in front of the vehicle 100 as illustrated in FIG. 9 . Asillustrated in FIG. 9 , when the retroreflective object 401 is a roadsign installed in the vicinity of the road, the retroreflective object401 is supported by, for example, a support portion 403 that is a metalpillar erected from the vicinity of the road. In FIG. 9 , H indicates ahorizontal line, the predetermined light distribution pattern 350 isindicated by the thick line, and the predetermined light distributionpattern 350 is a light distribution pattern formed on a vertical plane,for example, 25 m away from the vehicle 100. In addition, in FIG. 9 ,the left and right edges of each of the scanning regions SR1 to SR5 areindicated by the dotted lines.

As described above, the center region CA is a region where parts of thescanning regions SR1 to SR5 overlap each other. Therefore, the lightfrom the five light emitting elements 35-1 to 35-5 is superimposed oneach other in a region of the predetermined light distribution pattern350 illustrated in FIG. 9 overlapping the center region CA. Note thatthis superimposition of light also includes superimposition of light inhuman vision. In addition, the light from the four light emittingelements is superimposed on each other in a region of the predeterminedlight distribution pattern 350 overlapping the first left region LS1 andthe first right region RS1, and the light from the three light emittingelements is superimposed on each other in a region of the predeterminedlight distribution pattern 350 overlapping the second left region LS2and the second right region RS2. In addition, the light from the twolight emitting elements is superimposed on each other in a region of thepredetermined light distribution pattern 350 overlapping the third leftregion LS3 and the third right region RS3, and the light from the onelight emitting element forms a region of the predetermined lightdistribution pattern 350 overlapping the fourth left region LS4 and thefourth right region RS4. As described above, each of the scanningregions SR1 to SR5 is set as the light amount non-change region 313. Inthis case, in a region of the predetermined light distribution pattern350 where the number of scanning regions overlapping each other islarge, the intensity of light in the predetermined light distributionpattern 350 increases. Therefore, in the light distribution pattern 350,the intensity of light in a region of the light distribution pattern 350overlapping the center region CA is the strongest, and the intensity oflight is weaker toward the outer side of the light distribution pattern350 in the left-right direction. In addition, a superimposition regionPA that coincides with a region of the predetermined light distributionpattern 350 including the regions CA, LS1 to LS3, and RS1 to RS3 is aregion where the light from at least two light emitting elements issuperimposed on each other, and the predetermined light distributionpattern 350 includes such superimposition region PA. Note that, in FIG.9 , the superimposition region PA is indicated by the alternate long andshort dash line.

(Step S5)

In the present step, the retroreflective object as the target object isdetected by the detection device 110, and the distance between theretroreflective object and the vehicle 100 is less than thepredetermined distance. In this case, the control unit 60 controls thedriving of the light source unit 30 and also controls the driving of thedrive unit 41. FIG. 10 is a diagram describing scanning of thecondensing spots SC1 to SC5 in the present step. FIG. 11 is a diagramillustrating a specific light distribution pattern 360 formed when thedistance between the retroreflective object 401 and the vehicle 100 isless than the predetermined distance. In addition, in FIG. 11 , the leftand right edges of each of the scanning regions SR1 to SR5 are indicatedby the dotted lines. Here, the description will be given assuming thatthe retroreflective object overlaps the superimposition region PA.

In the present step, the control unit 60 sets a region where theretroreflective object overlaps the superimposition region PA as apredetermined region AR on the basis of the signal from thedetermination unit 50. As illustrated in FIG. 11 , the predeterminedregion AR is a region extending linearly from the upper end to the lowerend of the superimposition region PA, and is located in the centerregion CA. Therefore, in a case where the predetermined region AR isformed in the light distribution pattern 350 illustrated in FIG. 9 , thelight from the five light emitting elements 35-1 to 35-5 is superimposedon each other in the predetermined region AR. The position of thepredetermined region AR in the left-right direction changes according tothe position of the retroreflective object 401 in the left-rightdirection with respect to the vehicle 100, and in the presentembodiment, the center of the predetermined region AR in the left-rightdirection substantially coincides with the center of the retroreflectiveobject 401 in the left-right direction. Note that the center of thepredetermined region AR in the left-right direction may not coincidewith the center of the retroreflective object 401 in the left-rightdirection. In addition, the width of the predetermined region AR in theleft-right direction changes according to the distance between thevehicle 100 and the retroreflective object 401. In the presentembodiment, the entire retroreflective object 401 overlaps thepredetermined region AR, and the width of the predetermined region AR inthe left-right direction is made wider as the distance from theretroreflective object 401 is shorter. Note that the width of thepredetermined region AR in the left-right direction may not changeaccording to the distance between the vehicle 100 and theretroreflective object 401. The width of the predetermined region AR inthe left-right direction is narrower than the width of the center regionCA, but may be the same as that of the center region CA.

Next, as illustrated in FIG. 10 , in a case where the light distributionpattern 350 illustrated in FIG. 9 is formed, the control unit 60 doesnot set the light amount change region 311 in some scanning regions ofthe scanning regions SR1 to SR5 in the light emitting elements 35-1 to35-5 that emit light to the predetermined region AR, which is notillustrated in FIG. 9 , and sets the light amount change region 311 inother some scanning regions. In the present embodiment, FIG. 10illustrates a state in which the light amount change region 311 is notset in the three scanning regions SR1, SR3, and SR5, and the lightamount change region 311 is set in the two scanning regions SR2 and SR4.Note that in FIG. 10 , similarly to FIG. 8 , the plurality of scanningregions SR1 to SR5 is displaced and arranged for easy viewing. The lightamount change region 311 corresponds to the predetermined region AR, theposition of the light amount change region 311 in the left-rightdirection is the same as that of the predetermined region AR, and thewidth of the light amount change region 311 in the left-right directionis the same as that of the predetermined region AR. In addition, thecontrol unit 60 sets the light amount non-change region 313 in a regionwhere the light amount change region 311 is not set in each of thescanning regions SR1 to SR5.

Note that, in a case where the predetermined region AR is located in thefirst left region LS1, when the light distribution pattern 350illustrated in FIG. 9 is formed, the light from the four light emittingelements 35-1 to 35-4 is superimposed on each other in the predeterminedregion AR. In this case, in a case where the light distribution pattern350 illustrated in FIG. 9 is formed, the control unit 60 does not setthe light amount change region 311 in some scanning regions of thescanning regions SR1 to SR4 in the light emitting elements 35-1 to 35-4that emit light to the predetermined region AR, and sets the lightamount change region 311 in other some scanning regions. Therefore, thecontrol unit 60 does not set the light amount change region 311 in somescanning regions of the scanning regions of the light emitting elementsthat emit light to the predetermined region AR in the light distributionpattern 350 formed when the distance between the target object and thevehicle 100 is equal to or more than the predetermined distance, andsets the light amount change region 311 in other some scanning regions.

In addition, when the distance between the target object and the vehicle100 is less than the predetermined distance, the number of scanningregions in which the light amount change region 311 is set changesaccording to the distance between the vehicle 100 and the target object.For example, in a case where the target object is the retroreflectiveobject 401, the number increases as the distance between the vehicle 100and the retroreflective object 401 is shorter. For example, in a casewhere the distance between the vehicle 100 and the retroreflectiveobject 401 is shorter than the distance in the state illustrated in FIG.11 , the light amount change region 311 in which the distance is largerthan that in the state illustrated in FIG. 10 is set. In this case, forexample, the light amount change region 311 is set in the three scanningregions SR1, SR2, and SR4. Note that, for example, in a case where thetarget object is a human, the number of scanning regions in which thelight amount change region 311 is set increases as the distance betweenthe vehicle 100 and the human is longer. Note that the number ofscanning regions in which the light amount change region 311 is set maynot change according to the distance between the vehicle 100 and aretroreflective object or a human as a target object. In addition, thescanning region where the light amount change region 311 is not set isnot particularly limited, and may be changed according to the positionof the target object in the left-right direction with respect to thesuperimposition region PA.

In addition, the control unit 60 sets the second predetermined value onthe basis of the information from the determination unit 50. In a casewhere the target object is a retroreflective object, that is, in a casewhere a signal indicating that the target object is a retroreflectiveobject is input to the control unit 60, the control unit 60 sets thesecond predetermined value to a predetermined value lower than the firstpredetermined value. Note that, in a case where the target object is ahuman, that is, in a case where a signal indicating that the targetobject is a human is input to the control unit 60, the control unit 60sets the second predetermined value to be higher than the firstpredetermined value. In the flowchart illustrated in FIG. 7 , since thetarget object is the retroreflective object 401, the control unit 60sets the second predetermined value to a predetermined value lower thanthe first predetermined value.

Next, in a case where the target object is the retroreflective object401, the control unit 60 controls the light emitting elements 35-1,35-3, and 35-5 such that the light amount of light emitted from thelight emitting elements 35-1, 35-3, and 35-5 corresponding to thecondensing spots SC1, SC3, and SC5 for scanning the scanning regionsSR1, SR3, and SR5 where the light amount change region 311 is not setbecomes the first predetermined value. In addition, in a case where thetarget object is the retroreflective object 401, the control unit 60controls the light emitting elements 35-2 and 35-4 such that the lightamount of light emitted from the light emitting elements 35-2 and 35-4corresponding to the condensing spots SC2 and SC4 becomes the firstpredetermined value during a period in which the condensing spots SC2and SC5 for scanning the scanning regions SR2 and SR4 in which the lightamount change region 311 is set pass through the light amount non-changeregion 313. In addition, in a case where the target object is theretroreflective object 401, the control unit 60 controls the lightemitting elements 35-2 and 35-4 such that the light amount of lightemitted from the light emitting elements 35-2 and 35-4 corresponding tothe condensing spots SC2 and SC4 becomes the second predetermined valueduring a period in which the condensing spots SC2 and SC4 pass throughthe light amount change region 311. Then, the processing returns to StepS1.

When the light emitting elements 35-1 to 35-5 controlled as describedabove emit light, the light is reflected toward the projection lens 43by the reflector 39 rotated by the drive unit 41. The reflected lightpasses through the projection lens 43, is emitted to the front of thevehicle 100, and scans in the left-right direction of the vehicle 100.By this light scanning, the specific light distribution pattern 360illustrated in FIG. 11 is formed in front of the vehicle 100. Asdescribed above, the light amount of light emitted from the lightemitting elements 35-2 and 35-4 corresponding to the condensing spotsSC2 and SC4 becomes the second predetermined value lower than the firstpredetermined value during a period in which the condensing spots SC2and SC4 pass through the light amount change region 311. Therefore, thelight amount emitted from the condensing spots SC2 and SC4 to thepredetermined region AR changes so as to be smaller than the lightamount in a case where the determination unit 50 determines that theretroreflective object does not satisfy the predetermined requirement.Accordingly, when the specific light distribution pattern 360illustrated in FIG. 11 is compared with the predetermined lightdistribution pattern 350 illustrated in FIG. 9 , the light amount oflight emitted to the predetermined region AR in the specific lightdistribution pattern 360 is smaller than the light amount of lightemitted to the region corresponding to the predetermined region AR inthe predetermined light distribution pattern 350, and the light amountof light emitted to the retroreflective object 401 becomes smaller.

Here, as described above, in a case where the target object overlaps aregion where at least two scanning regions overlap each other, thecontrol unit 60 does not set the light amount change region 311 in somescanning regions, and sets the light amount change region 311 in othersome scanning regions. Therefore, in the present step, the control unit60 controls the light source unit 30 such that the light amount of lightemitted from some light emitting elements to the predetermined region ARoverlapping the target object does not change and the light amount oflight emitted from other some light emitting elements to thepredetermined region AR overlapping the target object changes among thelight emitting elements that emit light to the predetermined region ARoverlapping the target object in the superimposition region PA where thelight from at least two light emitting elements in the lightdistribution pattern 350 illustrated in FIG. 9 is superimposed on eachother.

Note that, in the present step, when a human as a target object isdetected by the detection device 110 and the determination unit 50determines that the human satisfies the predetermined requirement, thecontrol unit 60 sets the second predetermined value to be higher thanthe first predetermined value as described above. In a case where thesecond predetermined value is higher than the first predetermined value,the light amount emitted from the light emitting elements 35-2 and 35-4to the predetermined region AR is larger than the light amount in a casewhere the determination unit 50 determines that the human does notsatisfy the predetermined requirement. When the light amount increases,the light amount emitted to the predetermined region AR overlapping thehuman in the specific light distribution pattern 360 when thedetermination unit 50 determines that the human satisfies thepredetermined requirement is larger than the light amount emitted to theregion corresponding to the predetermined region AR in the predeterminedlight distribution pattern 350 when the determination unit 50 determinesthat the human does not satisfy the predetermined requirement.Accordingly, the light amount of light emitted to the human is larger ina state in which the human satisfies the predetermined requirement thanin a state in which the human does not satisfy the predeterminedrequirement.

In addition, in the present step, as described above, in a case wherethe distance between the retroreflective object 401, which is the targetobject, and the vehicle 100 is less than the predetermined distance, thenumber of scanning regions in which the light amount change region 311is set increases as the distance between the vehicle 100 and theretroreflective object 401 decreases. Therefore, the closer the distancebetween the vehicle 100 and the retroreflective object 401, the smallerthe light amount of light emitted to the retroreflective object. Inaddition, as described above, in a case where the distance between thehuman, which is the target object, and the vehicle 100 is less than thepredetermined distance, the number of scanning regions in which thelight amount change region 311 is set increases as the distance betweenthe vehicle 100 and the human increases. Therefore, the farther thedistance between the vehicle 100 and the human, the larger the lightamount of light emitted to the human. Therefore, the control unit 60controls the light source unit 30 such that the light amount of lightemitted from some light emitting elements to the predetermined region ARoverlapping the target object does not change and the light amount oflight emitted from other some light emitting elements to thepredetermined region AR overlapping the target object changes among thelight emitting elements that emit light to the predetermined region ARoverlapping the target object in the superimposition region PA describedabove according to the distance between the vehicle 100 and the targetobject.

By the way, for example, in a case where light emitted from a vehicleheadlight provided in a self-vehicle irradiates a retroreflective objectsuch as a sign, a part of the light is directed from the retroreflectiveobject to the self-vehicle as reflected light, and glare may be given tothe driver of the self-vehicle. In addition, when the light amount oflight emitted from the vehicle headlight and irradiating a human such asa pedestrian is small, it may be difficult for the driver to visuallyrecognize the human. Accordingly, there is a demand for easier driving.

Therefore, the vehicle headlight 10 of the present embodiment includesthe light source unit 30, the reflector 39, and the control unit 60 thatcontrols the light source unit 30. The light source unit 30 includes theplurality of light emitting elements 35-1 to 35-5. The reflector 39repeats the periodic motion to reflect the light from the plurality oflight emitting elements 35-1 to 35-5 and periodically scan the light toform the predetermined light distribution pattern 350. The predeterminedlight distribution pattern 350 includes the superimposition region PAwhere the light from at least two light emitting elements issuperimposed on each other. In a case where a signal indicating that thetarget object located in front of the vehicle 100 is detected is inputfrom the detection device 110, the control unit 60 controls the lightsource unit 30 such that the light amount of light emitted from somelight emitting elements to the predetermined region AR overlapping thetarget object does not change and the light amount of light emitted fromother some light emitting elements to the predetermined region ARoverlapping the target object changes among the light emitting elementsthat emit light to the predetermined region AR overlapping the targetobject in the superimposition region PA.

In the vehicle headlight 10 of the present embodiment, the lightdistribution pattern of the emitted light changes according to thesituation in front of the vehicle 100, and the light amount of lightemitted to the target object changes. In addition, in the vehicleheadlight 10 of the present embodiment, even in a case where a targetobject is detected, the light amount of light emitted from some lightemitting elements to the predetermined region AR overlapping the targetobject does not change. Therefore, in the vehicle headlight 10 of thepresent embodiment, even when the light distribution pattern of theemitted light is changed, the light from some light emitting elements isemitted to the target object. When the light irradiates the targetobject, the difficulty in visually recognizing the target object can besuppressed and the driving can be facilitated as compared with the casewhere the light distribution pattern of the emitted light changes andthe target object is not irradiated with the light. In addition, in thevehicle headlight 10 of the present embodiment, the number of lightemitting elements that change the light amount of light emitted issmaller than that in a case where the light amount of light emitted fromall the light emitting elements that emit light to the predeterminedregion AR overlapping the target object is changed. Therefore, with thevehicle headlight 10 of the present embodiment, the control of the lightsource unit 30 by the control unit 60 can be simplified as compared withsuch a case. Note that, in a case where the target object is detected bythe detection device and the target object is the retroreflective object401, for example, as illustrated in FIG. 11 , the light amount of lightemitted to the retroreflective object 401 changes. In a case where theretroreflective object 401 reflects the light from the vehicle headlight10, the intensity of reflected light from the retroreflective object 401to the self-vehicle tends to increase as the intensity of light emittedto the retroreflective object 401 increases. In the vehicle headlight 10of the present embodiment, since the light amount of light emitted tothe retroreflective object 401 is reduced, the intensity of light to theretroreflective object 401 is suppressed and the intensity of reflectedlight can be suppressed as compared with the case where the light amountof light emitted to the retroreflective object 401 does not change.Therefore, in the vehicle headlight 10 of the present embodiment,impartment of glare to the driver of the self-vehicle can be suppressed,and driving can be facilitated. In addition, in the vehicle headlight 10of the present embodiment, in a case where the target object is detectedby the detection device and the target object is a human, the lightamount of light emitted to the human changes. In the vehicle headlight10 of the present embodiment, the light amount of light emitted to thehuman increases, and thus, in the vehicle headlight 10, the human can beeasily visually recognized and the driving can be facilitated ascompared with the case where the light amount of light emitted to thehuman does not change. Note that the control unit 60 may determine thatthe target object is detected when a determination result of thedetermination unit 50 indicating whether the target object satisfies thepredetermined requirement is input. In this case, the detection device110 may not output the signal indicating that the target object isdetected to the control unit 60.

In addition, in the vehicle headlight 10 of the present embodiment, thewidth of the predetermined region AR in the left-right directionoverlapping the target object changes according to the distance betweenthe vehicle 100 and the target object. From the viewpoint of the driver,the target object looks larger as the distance between the vehicle 100and the target object is shorter. Therefore, with such a configuration,the light amount of light emitted to the target object can beappropriately changed as compared with the case where the width of thepredetermined region AR in the left-right direction in which the lightamount of emitted light changes does not change according to thedistance between the vehicle 100 and the target object.

In addition, in the vehicle headlight 10 of the present embodiment, thecontrol unit 60 controls the light source unit 30 such that the lightamount of light emitted from some light emitting elements to thepredetermined region AR overlapping the target object does not changeand the light amount of light emitted from other some light emittingelements to the predetermined region AR overlapping the target objectchanges among the light emitting elements that emit light to thepredetermined region AR overlapping the target object in thesuperimposition region PA described above according to the distancebetween the vehicle 100 and the target object. Therefore, the lightamount of light emitted to the target object changes according to thedistance between the vehicle 100 and the target object. The driver tendsto have difficulty in visually recognizing the human as the distancebetween the vehicle and the human is longer. In the vehicle headlight 10of the present embodiment, the farther the distance between the vehicleand the human, the larger the light amount of light emitted to thehuman. Therefore, in the vehicle headlight 10 of the present embodiment,the human can be easily visually recognized and the driving can befacilitated as compared with the case where the light amount of lightemitted to the human does not change according to the distance betweenthe vehicle 100 and the human. In addition, in a case where theretroreflective object reflects the light from the vehicle headlight 10,the intensity of reflected light from the retroreflective object to theself-vehicle tends to increase as the distance between the self-vehicleand the retroreflective object is shorter. In the vehicle headlight 10of the present embodiment, the closer the distance between the vehicle100 and the retroreflective object, the smaller the light amount oflight emitted to the retroreflective object. Therefore, in the vehicleheadlight 10 of the present embodiment, impartment of glare to thedriver of the self-vehicle can be suppressed and the driving can befacilitated as compared with the case where the light amount of lightemitted to the retroreflective object does not change according to thedistance between the vehicle 100 and the retroreflective object.

Note that, in Step S5, the control unit 60 does not need to controlother some light emitting elements such that the light amount of lightemitted from other some light emitting elements different from somelight emitting elements toward the predetermined region AR overlappingthe target object among the light emitting elements that emit light tothe predetermined region AR overlapping the target object in thesuperimposition region PA always becomes the second predetermined value.For example, the control unit 60 may set the light amount change region311 in a predetermined scanning period. Then, the control unit 60 maycontrol other some light emitting elements such that the light amount oflight emitted from other some light emitting elements described abovetoward the predetermined region AR becomes the second predeterminedvalue in the period in which the condensing spot passes through thelight amount change region 311 in the predetermined scanning period. Inaddition, in a case where the number of other some light emittingelements described above is plural, the light amounts of light emittedfrom the plurality of light emitting elements toward the predeterminedregion AR may be different from each other. For example, in a case whereother some light emitting elements are the two light emitting elements35-2 and 35-4 and the target object is a retroreflective object as inthe above embodiment, the control unit 60 may control the two lightemitting elements 35-2 and 35-4 such that the light amount of lightemitted from the light emitting element 35-2 toward the predeterminedregion AR becomes the second predetermined value and the light amount oflight emitted from the light emitting element 35-4 toward thepredetermined region AR becomes a third predetermined value lower thanthe second predetermined value.

In addition, in Step S5, the control unit 60 does not need to controlthe light source unit 30 such that the light amount of light emittedfrom some light emitting elements to the predetermined region AR doesnot change and the light amount of light emitted from other some lightemitting elements to the predetermined region AR changes among the lightemitting elements that emit light to the predetermined region ARoverlapping the target object in the superimposition region PA accordingto the distance between the vehicle 100 and the target object. Forexample, in a case where the detection device 110 can detect aretroreflective object as a target object and can detect the intensityof light directed from the retroreflective object to the vehicle 100,the control unit 60 may control the light source unit 30 such that thelight amount of light emitted from some light emitting elements to thepredetermined region AR does not change and the light amount of lightemitted from other some light emitting elements to the predeterminedregion AR decreases among the light emitting elements that emit light tothe predetermined region AR overlapping the retroreflective object inthe superimposition region PA according to the intensity of lightdirected from the retroreflective object to the vehicle 100. With such aconfiguration, the impartment of glare to the driver of the self-vehiclecan be appropriately suppressed. Note that the detection device 110detects the intensity of light from the retroreflective object towardthe vehicle 100 on the basis of, for example, a luminance value in thecaptured image. In addition, for example, in a case where the detectiondevice 110 can detect a retroreflective object as a target object andcan detect an angle formed by the traveling direction of the vehicle 100and a direction from the vehicle 100 toward the retroreflective object,the control unit 60 may control the light source unit 30 such that, asthe angle is smaller, the light amount of light emitted from some lightemitting elements to the predetermined region AR does not change, andthe light amount of light emitted from other some light emittingelements to the predetermined region AR decreases among the lightemitting elements that emit light to the predetermined region ARoverlapping the retroreflective object in the superimposition region PA.In general, in a light distribution pattern of light emitted from avehicle headlight, the intensity of light tends to increase to a centerside. Therefore, the intensity of light emitted to the target objecttends to increase as the angle described above decreases. Therefore, forexample, by controlling the light source unit 30 such that the smallerthe angle described above is, the smaller the light amount of lightemitted to the predetermined region AR overlapping the retroreflectiveobject is, the impartment of glare to the driver of the self-vehicle canbe appropriately suppressed. In addition, in a case where the number oflight emitting elements 35 that emit light to the predetermined regionAR overlapping the target object is three or more, the control unit 60may change the number of other some light emitting elements and changethe light amount of light emitted from the other some light emittingelements to the predetermined region AR overlapping the target object.

In addition, the control unit 60 may change the scanning region in whichthe light amount change region 311 is set according to the position ofthe predetermined region AR in the left-right direction. Hereinafter, amodification in which the scanning region in which the light amountchange region 311 is set changes will be described. Note that the sameor equivalent components as those of the embodiment described above aredesignated by the same reference numerals and duplicated descriptionwill be omitted unless otherwise specified.

In the present modification, for example, as illustrated in FIG. 12 ,the scanning regions SR1 to SR5 corresponding to the respective lightemitting elements 35-1 to 35-5 are divided into three regions: pairs ofend portions EP1-1 to EP1-5 and EP2-1 to EP2-5, and center portions CP1to CP5 in the left-right direction, which is the scanning direction.Note that, in FIG. 12 , the scanning regions SR1 to SR5 are arranged tobe displaced vertically, and the sizes of the pairs of end portions withrespect to the respective scanning regions are larger than the actualsizes for easy understanding.

One end portions EP1-1 to EP1-5 are regions including the left-side endsof the scanning regions SR1 to SR5.

Widths W1-1 to W1-5 in the left-right direction are widths equal to orlarger than the widths of the condensing spots SC1 to SC5 in theleft-right direction, and are, for example, ten times the widths of thecondensing spots SC1 to SC5 in the left-right direction. The other endportions EP2-1 to EP2-5 are regions including the right-side ends of thescanning regions SR1 to SR5. Widths W2-1 to W2-5 in the left-rightdirection are widths equal to or larger than the widths of thecondensing spots SC1 to SC5 in the left-right direction, and are, forexample, ten times the widths of the condensing spots SC1 to SC5 in theleft-right direction. The center portions CP1 to CP5 are regionssandwiched between the one end portions EP1-1 to EP1-5 and the other endportions EP2-1 to EP2-5.

The scanning regions SR1 to SR5 are arranged to be displaced in theleft-right direction, and centers C1 to C5 of the center portions CP1 toCP5 in the left-right direction are also displaced from each other inthe left-right direction. However, a part of each of the center portionsCP1 to CP5 overlaps a part of the central portions of all the otherscanning regions. In addition, the respective end portions EP1-1 toEP1-5 and EP2-1 to EP2-5 do not overlap the end portions of all theother scanning regions.

FIG. 13 is a diagram describing an example of setting of the lightamount change region 311 in Step S5 in the present modification. Notethat, in FIG. 13 , the sizes of the pairs of end portions with respectto the respective scanning regions are larger than the actual size foreasy understanding. In addition, in FIG. 13 , the light amount changeregion 311 is not set in the three scanning regions SR1, SR2, and SR3,and the light amount change region 311 is set in the two scanningregions SR4 and SR5 in Step S5. In addition, the predetermined region ARis located in the center portions CP4 and CP5 of all the scanningregions SR4 and SR5 in which the light amount change region 311 is set.Note that, in the example illustrated in FIG. 13 , the predeterminedregion AR is also located in the center portions CP1 to CP3 of thescanning regions SR1 to SR3 in which the light amount change region 311is not set. In such a state, for example, when the predetermined regionAR moves in the left-right direction as the vehicle 100 moves, the lightamount change region 311 also moves in the left-right direction.Therefore, as illustrated in FIG. 14 , in the two scanning regions SR4and SR5, the end portion and the light amount change region 311 mayoverlap each other. In other words, in the two scanning regions SR4 andSR5, the end portion may overlap the predetermined region AR. Here, inthe example illustrated in FIG. 14 , one end portion EP1-5 of thescanning region SR5 and the predetermined region AR overlap, and thispredetermined region AR is located in the center portions CP1 to CP4 ofthe scanning regions SR1 to SR4.

In a case where the predetermined region AR is changed from a firststate illustrated in FIG. 13 to a second state illustrated in FIG. 14 ,the control unit 60 controls the light source unit 30 in the mannerdescribed below. The first state is a state in which the predeterminedregion AR is located in the center portions CP4 and CP5 of all thescanning regions SR4 and SR5 in which the light amount change region 311is set as illustrated in FIG. 13 . In addition, the second state is astate in which, as illustrated in FIG. 14 , the predetermined region ARoverlaps one end portion EP1-5 of the scanning region SR5 and is locatedin the center portions CP1 to CP3 of the scanning regions SR1 to SR3 inwhich the light amount change region 311 is not set. The control unit 60controls the light source unit 30 such that the light amount emitted tothe predetermined region AR from the light emitting elementcorresponding to the scanning region where the end portion and thepredetermined region AR overlap among the light emitting elements 35-4and 35-5 returns to the light amount emitted to the predetermined regionAR before the light amount is changed. Specifically, the control unit 60removes the light amount change region 311 from the scanning region SR5in which the end portion EP1-5 and the predetermined region AR overlap.Therefore, the light amount emitted to the predetermined region AR fromthe light emitting element 35-1 corresponding to the scanning region SR5returns to the light amount emitted to the predetermined region ARbefore the light amount change region 311 is provided in the scanningregion SR5. That is, the light amount emitted from the light emittingelement 35-1 to the predetermined region AR returns to the light amountemitted to the predetermined region AR in a case where the determinationunit 50 does not determine that the target object satisfies thepredetermined requirement.

In addition, the control unit 60 controls the light source unit 30 suchthat the light amount emitted to the predetermined region AR in thesecond state becomes the light amount in the first state by changing thelight amount of light emitted to the predetermined region AR from atleast one light emitting element corresponding to the scanning region inwhich the predetermined region AR is located in the center portion amongthe light emitting elements 35-1 to 35-3. Here, in the presentmodification, similarly to the above embodiment, the light amount oflight emitted from each light emitting element 35-i when the condensingspot SCi passes through the light amount non-change region 313 is thefirst predetermined value. Therefore, the control unit 60 provides thelight amount change region 311 in one scanning region corresponding tothe scanning region in which the predetermined region AR is located inthe center portion among the three scanning regions SR1 to SR3. Here,since the end portions of the three scanning regions SR1 to SR3 do notoverlap the predetermined region AR, the light amount change region 311is provided in any one of the three scanning regions SR1 to SR3. In thepresent modification, the control unit 60 provides the light amountchange region 311 in the scanning region SR2 in which the distancebetween the predetermined region AR and the centers C1 to C3 of thecenter portions CP1 to CP3 in the left-right direction is the shortestamong the three scanning regions SR1 to SR3. Therefore, the light amountemitted from the light emitting element 35-2 corresponding to thescanning region SR2 to the predetermined region AR changes, and thelight amount emitted to the predetermined region AR in the second statebecomes the light amount in the first state. Then, the processingreturns to Step S1 from Step S5. Note that it is sufficient if thecontrol unit 60 controls the light source unit 30 such that the lightamount emitted to the predetermined region AR in the second statebecomes the light amount in the first state by providing the lightamount change region 311 in any one of the three scanning regions SR1 toSR3. A method of selecting the scanning region is not particularlylimited, and the light amount change region 311 may be provided in aplurality of scanning regions. When the light amount change region 311is provided in the plurality of scanning regions, the light amount oflight emitted from the light emitting element when the condensing spotpasses through the light amount change region 311 is adjusted such thatthe light amount emitted to the predetermined region AR in the secondstate becomes the light amount in the first state.

Here, in the present modification, as in the above-described embodiment,a light distribution pattern is formed by periodic scanning of lightfrom the plurality of light emitting elements 35-1 to 35-5. In such avehicle headlight, for example, when the predetermined region ARoverlapping the target object is located in the vicinity of an end inthe scanning direction of the scanning region SR1 through which thecondensing spot SCi of light from the light emitting element 35-ipasses, the distance between this end and the predetermined region ARmay be narrower than the width of the condensing spot SCi in thescanning direction. By the way, the shortest length that allows lightscanning is the width of the condensing spot SCi in the scanningdirection. Therefore, in the case as described above, the light amountemitted to the predetermined region AR cannot be changed withoutchanging the light amount emitted between the end and the predeterminedregion AR. Therefore, the light amount emitted between theabove-described end and the predetermined region AR is also changedtogether with the predetermined region AR, and the region where thelight amount is changed may suddenly become large, and the driver mayfeel a sense of discomfort.

The vehicle headlight 10 of the present modification further includesthe determination unit 50 that determines whether the target objectsatisfies the predetermined requirement that the light amount of lightreflected from the target object is equal to or more than thepredetermined value when a signal indicating the state of the targetobject is input from the detection device 110. In addition, in thevehicle headlight 10 of the present modification, as described above,the scanning regions SR1 to SR5 through which the condensing spots SC1to SC5 of the light from the light emitting elements 35-1 to 35-5scanned by the reflector 39 in the predetermined light distributionpattern 350 pass are divided into the pairs of end portions EP1-1 toEP1-5 and EP2-1 to EP2-5 and the center portions CP1 to CP5. One endportions EP1-1 to EP1-5 are regions including the left-side ends of thescanning regions SR1 to SR5, and the other end portions EP2-1 to EP2-5are regions including the right-side ends of the scanning regions SR1 toSR5. The center portions CP1 to CP5 are regions sandwiched between theone end portions EP1-1 to EP1-5 and the other end portions EP2-1 toEP2-5 in the scanning direction. The widths of the end portions EP1-1 toEP1-5 and EP2-1 to EP2-5 in the scanning direction in the scanningregions SR1 to SR5 are equal to or larger than the widths of thecondensing spots SC1 to SC5 in the scanning direction. The scanningregions SR1 to SR5 are arranged to be displaced in the scanningdirection, a part of the center portions CP1 to CP5 of the scanningregions SR1 to SR5 overlaps a part of the center portions of all theother scanning regions, and the end portions EP1-1 to EP1-5 and EP2-1 toEP2-5 of the scanning regions SR1 to SR5 do not overlap the end portionsof all the other scanning regions. Then, in a case where thepredetermined region AR is changed from the first state to the secondstate, the control unit 60 controls the light source unit 30 in themanner described below. The first state here is a state in which thepredetermined region AR is located in the center portions CP4 and CP5 ofall the scanning regions SR4 and SR5 corresponding to the light emittingelements 35-4 and 35-5 in which the light amount of light emitted to thepredetermined region AR is changed. In addition, the second state is astate in which the predetermined region AR overlaps an end portion of atleast one scanning region corresponding to the light emitting elements35-4 and 35-5 in which the light amount of light emitted to thepredetermined region AR is changed as the predetermined region AR movesin the scanning direction, and the predetermined region AR is located inthe center portion in the scanning region corresponding to at least onelight emitting element of the light emitting elements 35-1 to 35-3 inwhich the light amount of light emitted to the predetermined region ARis not changed. The control unit 60 controls the light source unit 30such that the light amount emitted to the predetermined region AR fromthe light emitting element 35-5 corresponding to the scanning region SR5in which the predetermined region AR overlaps the end portion among thelight emitting elements 35-4 and 35-5 in which the light amount of lightemitted to the predetermined region AR is changed returns to the lightamount emitted to the predetermined region AR in a case where thedetermination unit 50 does not determine that the target objectsatisfies the predetermined requirement. Therefore, with the vehicleheadlight 10 of the present modification, the distance between thepredetermined region AR and the end of the scanning region correspondingto the light emitting element in which the light amount of light emittedto the predetermined region AR is changed can be prevented from beingless than the width of the condensing spot in the scanning direction. Inaddition, the control unit 60 controls the light source unit 30 suchthat the light amount emitted to the predetermined region AR in thesecond state becomes the light amount in the first state by changing thelight amount emitted to the predetermined region AR from at least onelight emitting element corresponding to the scanning region in which thepredetermined region AR is located in the center portion among the lightemitting elements 35-1 to 35-3 in which the light amount of lightemitted to the predetermined region AR is not changed. Therefore, withthe vehicle headlight 10 of the present modification, a change in thelight amount emitted to the vicinity of the predetermined region AR canbe suppressed, the brightness of the predetermined region AR can beprevented from changing, and the driver can be suppressed from feeling asense of discomfort.

In addition, in the vehicle headlight 10 of the present modification,the predetermined region AR in the second state is located in the centerportion of the scanning region corresponding to two or more lightemitting elements among the light emitting elements 35-1 to 35-3 inwhich the light amount of light emitted to the predetermined region ARis not changed. Then, in the case of changing from the first state tothe second state, the light amount emitted to the predetermined regionAR from the light emitting element 35-2 corresponding to the scanningregion SR2 having the shortest distance between the predetermined regionAR and the centers C1 to C3 in the scanning direction of the centerportions CP1 to CP3 among the two or more light emitting elements of thelight emitting elements 35-1 to 35-3 in which the light amount of lightemitted to the predetermined region AR is not changed changes.Therefore, even when the predetermined region AR further moves to oneside or the other side in the scanning direction, the end portion of thescanning region SR2 corresponding to the light emitting element 35-2 inwhich the light amount of light emitted to the predetermined region ARis changed in the case of changing from the first state to the secondstate and the predetermined region AR can be made less likely to overlapeach other. Accordingly, with the vehicle headlight 10 of the presentmodification, it is possible to suppress an increase in the number oftimes the control unit 60 controls the light source unit 30 as describedabove.

Note that, in the present modification, the light amount change region311 is provided in the scanning regions SR4 and SR5 in the first state.However, the scanning region in which the light amount change region 311is provided and the number of scanning regions in which the light amountchange region 311 is provided are not particularly limited. In addition,the length of each scanning region in the scanning direction is also notparticularly limited. In addition, the widths of the end portions inthese scanning regions may be different from each other or may be thesame. In addition, the widths of these scanning regions in a directionperpendicular to the scanning direction may be different from each otheror may be the same. In addition, these scanning regions may also bedisplaced in the scanning direction and also in a directionperpendicular to the scanning direction. In addition, a part of thelight distribution pattern may be formed by scanning light from the fivelight emitting elements 35-1 to 35-5, and another part of the lightdistribution pattern may be formed by scanning light from another lightemitting element.

(Second Embodiment)

Next, a second embodiment as a second aspect of the present inventionwill be described. Note that the same or equivalent components as thoseof the first embodiment are designated by the same reference numeralsand duplicated description will be omitted unless otherwise specified.In a vehicle headlight 10 of the present embodiment, the configurationof a light source unit 30 in lighting tools 20 a and 20 b is differentfrom the configuration of the light source unit 30 in the lighting tools20 a and 20 b of the first embodiment. Since the configurations of thelighting tools 20 a and 20 b of the present embodiment are the same, theconfigurations of the lighting tools 20 a and 20 b will be describedusing the lighting tool 20 a.

FIG. 15 is a diagram schematically illustrating the lighting tool 20 aof the present embodiment. As illustrated in FIG. 15 , in the lightingtool 20 a of the present embodiment, a plurality of light source units30 is arranged.

In FIG. 15 , each light source unit 30 is indicated by the broken line.The broken line is described for convenience in order to illustrate eachlight source unit 30, and does not mean that the shape of each lightsource unit 30 is a broken line-like shape. The light source units 30are arranged in a row along one direction which is the up-down directionin the sheet of paper of FIG. 15 . In addition, each light source unit30 includes a plurality of light emitting elements 35 mounted on acircuit board 33. The plurality of light emitting elements 35 isarranged in a row along another direction different from the onedirection. The other direction is, for example, a direction orthogonalto the one direction. FIG. 15 illustrates an example in which the twolight source units 30 are arranged in a row along the one direction. Inaddition, FIG. 15 illustrates an example in which five light emittingelements 35 are arranged in a row along the other direction in somelight source unit 30 a among the plurality of light source units 30, andtwo light emitting elements 35 are arranged in a row along the otherdirection in other some light source unit 30 b. The light source unit 30a corresponds to the light source unit 30 of the first embodiment. Notethat the number of light source units 30 and the number of lightemitting elements 35 in each light source unit 30 are not particularlylimited. In addition, for example, each light source unit 30 may beconfigured to include one light emitting element 35.

In each light source unit 30, power is supplied to each light emittingelement 35 via the circuit board 33. The light amount of light emittedfrom each light emitting element 35 is adjusted by adjusting the powersupplied to each light emitting element 35. Light is emitted toward areflector 39. Reflection blades 39 a of the reflector 39 reflect lightfrom the plurality of light source units 30 toward a projection lens 43.

In the present embodiment, when the plurality of light source units 30emit light toward the reflector 39 and the reflector 39 rotates, thereflector 39 repeats a periodic motion to reflect the light from theplurality of light source units 30 toward the projection lens 43 side,and scans the light in the left-right direction of a vehicle 100. Thelight passes through the projection lens 43, is emitted to the front ofthe vehicle 100, and scanned in the left-right direction of the vehicle100, and a first light distribution pattern 201 and a second lightdistribution pattern 203 are formed on a vertical plane 200 in front ofthe vehicle 100. The first light distribution pattern 201 is a lightdistribution pattern formed by scanning the light from the light sourceunit 30 a, and the second light distribution pattern 203 is a lightdistribution pattern formed by scanning the light from the light sourceunit 30 b. The first light distribution pattern 201 partially overlapsthe second light distribution pattern 203 in the up-down direction ofthe vehicle 100. For example, when the first light distribution pattern201 and the second light distribution pattern 203 have a rectangularshape horizontally long in the left-right direction of the vehicle 100,an upper end portion of the first light distribution pattern 201overlaps a lower end portion of the second light distribution pattern203. Here, the reflector 39 reflects the light from the plurality oflight source units 30 such that the first light distribution pattern 201partially overlaps the second light distribution pattern 203 in theup-down direction of the vehicle 100. Note that, in FIG. 15 , the firstlight distribution pattern 201 and the second light distribution pattern203 are illustrated in a rectangular shape, but the shape of the firstlight distribution pattern 201 and the second light distribution pattern203 is not limited to a rectangular shape.

FIGS. 16 and 17 are diagrams describing formation of the first lightdistribution pattern 201 and the second light distribution pattern 203.

FIG. 16 is a diagram illustrating a layout of light emitting elements35-1 to 35-7 of the plurality of light source units 30 of the presentembodiment. As described above, the light source unit 30 a includes thefive light emitting elements 35-1 to 35-5, and the light source unit 30b includes the two light emitting elements 35-6 to 35-7.

FIG. 17 is a diagram illustrating scanning regions SR1 to SR7 throughwhich condensing spots of light pass when the light from the lightemitting elements 35-1 to 35-7 is scanned by the reflector 39 to formthe first light distribution pattern 201 and the second lightdistribution pattern 203. A scanning region SR1 of the presentembodiment indicates a region through which a condensing spot formed bylight from an i-th (1≤i≤7) light emitting element 35-i passes. A set ofthe scanning regions SR1 to SR5 corresponds to the first lightdistribution pattern 201, and a set of the scanning regions SR6 to SR7corresponds to the second light distribution pattern 203.

Since the arrangement of the scanning regions SR1 to SR5 of the presentembodiment is the same as that of the scanning regions SR1 to SR5 of thefirst embodiment, the description thereof will be omitted. In FIG. 17 ,reference numerals of regions CA, LS1 to LS4, and RS1 to RS4 illustratedin FIG. 4 are omitted for clarity of illustration.

The scanning regions SR6 to SR7 have a rectangular shape horizontallylong in the left-right direction of the vehicle 100 and havesubstantially the same size. The scanning region SR6 is wider than thescanning region SR1.

The positions of the scanning regions SR6 to SR7 in the up-downdirection are substantially the same, and the positions in theleft-right direction are different. Accordingly, the scanning regionsSR6 to SR7 are arranged to be displaced from each other in theleft-right direction such that a part of each of the scanning regionsSR6 to SR7 overlaps a part of another scanning region. The overlappingregion overlaps a vertical line V and is located above a horizontal lineH. In addition, a lower end portion of each of the scanning regions SR6to SR7 overlaps a part of an upper end portion of each of the scanningregions SR1 to SR5. The overlapping region is located above thehorizontal line H.

FIG. 18 is a diagram describing control of the light emitting element35-i in the scanning region SR1. FIG. 18 is a diagram illustrating thescanning region SR1. In the scanning region SR1 illustrated in FIG. 18 ,a non-hatched range indicates a non-irradiation region 211, and ahatched range indicates an irradiation region 213. The non-irradiationregion 211 indicates a region not irradiated with light in the firstlight distribution pattern 201 and the second light distribution pattern203, or a region irradiated with light in a small light amount notgiving glare to the driver of the vehicle 100 by reflected light from aretroreflective object in the first light distribution pattern 201 andthe second light distribution pattern 203. The irradiation region 213indicates a region irradiated with light in the first light distributionpattern 201 and the second light distribution pattern 203. The lightamount in the irradiation region 213 is larger than the light amount inthe non-irradiation region 211. The time chart of the present embodimentillustrating the turn-on/turn-off state of the light emitting element35-i is the same as the time chart illustrated in FIG. 6 .

In the irradiation region 213, a control unit 60 controls the luminanceof the light emitting element 35-i such that the light amount of lightemitted from the light emitting element 35-i corresponding to thecondensing spot SCi becomes a first predetermined value during a periodin which the condensing spot SCi passes through the irradiation region213. The first predetermined value indicates a value of the light amountof light emitted from the light emitting element 35-i in the irradiationregion 213. In addition, the first predetermined value is, for example,the maximum value of the light amount of light emitted from the lightemitting element 35-i, 80% of the maximum value, or the like.

In addition, in the non-irradiation region 211, the control unit 60controls the luminance of the light emitting element 35-i such that thelight amount of light emitted from the light emitting element 35-icorresponding to the condensing spot SCi becomes a second predeterminedvalue during a period in which the condensing spot SCi passes throughthe non-irradiation region 211. Specifically, as illustrated in FIGS. 6and 18 , the control unit 60 controls the light amount of light emittedfrom the light emitting element 35-i to the second predetermined valueat timing to at which a right end RE of the condensing spot SCi reachesthe non-irradiation region 211, and controls the light amount of lightemitted from the light emitting element 35-i to the first predeterminedvalue at timing tB at which a left end LE of the condensing spot SCireaches a right end of the non-irradiation region 211. The secondpredetermined value indicates a value of the light amount of lightemitted from the light emitting element 35-i in the non-irradiationregion 211. The second predetermined value of the present embodiment isa value smaller than the first predetermined value. The secondpredetermined value is, for example, 30% of the maximum value of thelight amount, zero, or the like. When the second predetermined value iszero, the light from the light emitting element 35-i is turned off.

Next, the operation of the vehicle headlight 10 in the presentembodiment will be described. A control flowchart of the operationincludes Steps S1 to S5 similarly to the control flowchart of the firstembodiment. Since Steps S1 to S3 of the present embodiment are the sameas Steps S1 to S3 of the first embodiment, the description thereof willbe omitted. Steps S4 to S5 of the present embodiment are different fromSteps S4 to S5 of the first embodiment, and will be described below.Note that a target object of the present embodiment is a retroreflectiveobject located diagonally forward left of the vehicle 100. In addition,hereinafter, the distance between the retroreflective object and thevehicle 100 may be simply referred to as a distance.

(Step S4)

In the present step, as in Step S4 of first embodiment, theretroreflective object is detected by a detection device 110, and thedistance is equal to or more than a predetermined distance, or theretroreflective object is not detected by the detection device 110. Inthis case, the control unit 60 controls the driving of the plurality oflight source units 30 and also controls the driving of a drive unit 41.FIG. 19 is a diagram describing scanning of condensing spots SC1 to SC7in the present step. FIG. 20 is a diagram illustrating the first lightdistribution pattern 201 and the second light distribution pattern 203in a case where the distance is equal to or more than a predetermineddistance. The first light distribution pattern 201 and the second lightdistribution pattern 203 illustrated in FIG. 20 are the same as thefirst light distribution pattern 201 and the second light distributionpattern 203 illustrated in FIG. 15 .

Here, first, scanning of the condensing spots SC1 to SC7 in the presentstep will be described with reference to FIG. 19 . In FIG. 19 , theplurality of scanning regions SR1 to SR7 is displaced and arranged foreasy viewing. The condensing spots SC1 to SC7 scan the scanning regionsSR1 to SR7 from the left to the right in the drawing. When the distanceis equal to or more than the predetermined distance and when theretroreflective object is not detected by the detection device 110, thecontrol unit 60 sets each of the scanning regions SR1 to SR7 as theirradiation region 213. Next, the control unit 60 controls the lightemitting elements 35-1 to 35-7 such that the light amount of lightemitted from the light emitting elements 35-1 to 35-7 corresponding tothe condensing spots SC1 to SC7 becomes the first predetermined value.

When the light emitting elements 35-1 to 35-7 controlled as describedabove emit light, the light is reflected toward the projection lens 43by the rotating reflector 39. In addition, the light passes through theprojection lens 43, is emitted to the front of the vehicle 100, andscans in the left-right direction of the vehicle 100. By this lightscanning, the first light distribution pattern 201 and the second lightdistribution pattern 203 are formed in front of the vehicle 100 asillustrated in FIG. 20 . As illustrated in FIG. 20 , when aretroreflective object 401 is a road sign installed in the vicinity ofthe road, the retroreflective object 401 is supported by, for example, asupport portion 403 that is a metal pillar erected from the vicinity ofthe road. In FIG. 20 , H indicates a horizontal line, the first lightdistribution pattern 201 and the second light distribution pattern 203are indicated by the thick lines, and the first light distributionpattern 201 and the second light distribution pattern 203 are a lightdistribution pattern formed on a vertical plane, for example, 25 m awayfrom the vehicle 100. The first light distribution pattern 201 partiallyoverlaps the second light distribution pattern 203 in the up-downdirection of the vehicle 100.

(Step S5) In the present step, the retroreflective object is detected bythe detection device 110, and the distance is less than thepredetermined distance. In this case, the control unit 60 controls thedriving of the plurality of light source units 30 and also controls thedriving of a drive unit 41. FIG. 21 is a diagram describing scanning ofcondensing spots SC1 to SC7 in the present step. FIG. 22 is a diagramillustrating the first light distribution pattern 201 and the secondlight distribution pattern 203 in a case where the distance is less thanthe predetermined distance. Here, the description will be given assumingthat the upper end portion of the first light distribution pattern 201partially overlaps the lower end portion of the second lightdistribution pattern 203 in the up-down direction of the vehicle 100,and the retroreflective object overlaps the second light distributionpattern 203, which is one of the first light distribution pattern 201and the second light distribution pattern 203.

In the present step, the control unit 60 detects a predetermined regionAR where the retroreflective object overlaps in the second lightdistribution pattern 203 on the basis of a signal from a determinationunit 50, and sets the predetermined region AR as the non-irradiationregion 211. The signal indicates the state of a target object such asthe presence position of the retroreflective object. Next, the controlunit 60 controls driving of the light source unit 30 a that emits lightfor forming the first light distribution pattern 201 and driving of thelight source unit 30 b that emits light for forming the second lightdistribution pattern 203. The driving of the light source unit 30 a andthe light source unit 30 b in the present step will be described below.

Here, first, scanning of the condensing spots SC1 to SC7 in the presentstep will be described with reference to FIG. 21 . In FIG. 21 ,similarly to FIG. 19 , the plurality of scanning regions SR1 to SR7 isdisplaced and arranged for easy viewing. The condensing spots SC1 to SC7scan the scanning regions SR1 to SR7 from the left to the right in thedrawing.

First, driving of the light source unit 30 a will be described. Thecontrol unit 60 sets each of the scanning regions SR1 to SR5 as theirradiation region 213. Next, the control unit 60 controls the lightemitting elements 35-1 to 35-5 such that the light amount of lightemitted from the light emitting elements 35-1 to 35-5 corresponding tothe condensing spots SC1 to SC5 becomes the first predetermined value.

Next, driving of the light source unit 30 b will be described. Thecontrol unit 60 sets the non-irradiation region 211 in a part of each ofthe scanning regions SR6 to SR7, and sets the irradiation region 213 inanother part of each of the scanning regions SR6 to SR7. The controlunit 60 controls the light emitting elements 35-6 and 35-7 such that thelight amount of light emitted from the light emitting elements 35-6 and35-7 corresponding to the condensing spots SC6 and SC7 becomes the firstpredetermined value during a period in which the condensing spots SC6and SC7 pass through the irradiation region 213. In addition, thecontrol unit 60 controls the light emitting elements 35-6 and 35-7 suchthat the light amount of light emitted from the light emitting elements35-6 and 35-7 corresponding to the condensing spots SC6 and SC7 becomesthe second predetermined value during a period in which the condensingspots SC6 and SC7 pass through the non-irradiation region 211.

When the light emitting elements 35-1 to 35-7 controlled as describedabove emit light, the light is reflected toward the projection lens 43by the rotating reflector 39. In addition, the light passes through theprojection lens 43, is emitted to the front of the vehicle 100, andscanned in the left-right direction of the vehicle 100, and the firstlight distribution pattern 201 and the second light distribution pattern203 are formed in front of the vehicle 100.

In the present step, in a case where the determination unit 50determines that the retroreflective object 401 satisfies a predeterminedrequirement, the light amount of light emitted to the predeterminedregion AR overlapping the retroreflective object 401 in the second lightdistribution pattern 203, which is one of the first light distributionpattern 201 and the second light distribution pattern 203, is smallerthan that in a case where the determination unit 50 determines that theretroreflective object 401 does not satisfy the predeterminedrequirement. Thus, the second light distribution pattern 203 isprojected in front of the vehicle 100 in a state where the light amountin the retroreflective object 401 is smaller than that in the secondlight distribution pattern 203 in Step S4.

Next, an example of control of the second predetermined value will bedescribed using numerical values. The second predetermined value is avalue of the light amount of light emitted to the predetermined regionAR. The numerical values used here are described for convenience so thatthe magnitude relationship of the light amount can be easily imaged, anddo not indicate actual numerical values of the light amount of lightemitted to the predetermined region AR.

Here, the description will be given assuming that light emitted from thelight emitting element 35-6 of the light source unit 30 b that emitslight emitted to the predetermined region AR is referred to as firstlight, and the light amount of the first light is referred to as a firstlight amount. In addition, the description will be given assuming thatlight emitted from the light emitting element 35-7 of the light sourceunit 30 b is referred to as second light, and the light amount of thesecond light is referred to as a second light amount.

In a case where the distance is equal to or more than the predetermineddistance, for example, the control unit 60 controls the light sourceunit 30 b such that the first light amount becomes “100” and the secondlight amount becomes “100”. In this case, the sum of the first lightamount and the second light amount is “200”.

On the other hand, in a case where the distance is less than thepredetermined distance, the control unit 60 controls the light sourceunit 30 b such that the first light amount becomes “80” and the secondlight amount becomes “80”. In this case, the sum of the first lightamount and the second light amount is “160”.

Next, a comparison between the sum “200” of the first light amount andthe second light amount in a case where the distance is equal to or morethan the predetermined distance and the sum “160” of the first lightamount and the second light amount in a case where the distance is lessthan the predetermined distance will be described. Comparing the sums,the control unit 60 controls the light source unit 30 b such that thesum of the first light amount and the second light amount becomessmaller in a case where the distance is less than the predetermineddistance than in a case where the distance is equal to or more than thepredetermined distance. Next, a comparison between the first lightamount “100” and the second light amount “100” in a case where thedistance is equal to or more than the predetermined distance and thefirst light amount “80” and the second light amount “80” in a case wherethe distance is less than the predetermined distance will be described.Comparing them, the control unit 60 controls the light source unit 30 bsuch that each of the first light amount and the second light amountbecomes smaller in a case where the distance is less than thepredetermined distance than in a case where the distance is equal to ormore than the predetermined distance.

Note that, in the present embodiment, it is sufficient if the sum of thefirst light amount and the second light amount becomes smaller in a casewhere the distance is less than the predetermined distance than in acase where the distance is equal to or more than the predetermineddistance as described above. For example, the control unit 60 maycontrol the light source unit 30 b such that one of the first lightamount and the second light amount becomes “80” and the other becomes“100”. Here, a comparison between the first light amount “100” and thesecond light amount “100” in a case where the distance is equal to ormore than the predetermined distance and the first light amount “80” andthe second light amount “100” in a case where the distance is less thanthe predetermined distance will be described. Comparing them, thecontrol unit 60 controls the light source unit 30 b such that the firstlight amount becomes smaller and the second light amount becomes thesame in a case where the distance is less than the predetermineddistance than in a case where the distance is equal to or more than thepredetermined distance.

When the sum of the first light amount and the second light amount iscontrolled as described above, the processing returns to Step S1.

By the way, in a case where light from a vehicle headlight provided in aself-vehicle irradiates a retroreflective object such as a sign, a partof the light is directed from the retroreflective object to theself-vehicle as reflected light, and glare may be given to the driver ofthe self-vehicle. Thus, there is a concern that the driver's visibilityis reduced.

Therefore, the vehicle headlight 10 of the present embodiment includesthe plurality of light source units 30, the reflector 39 that repeats aperiodic motion to reflect light from the plurality of light sourceunits 30 and scans the light in the left-right direction of the vehicle100, and the control unit 60 that controls the plurality of light sourceunits 30. The reflector 39 reflects the light from the plurality oflight source units 30 such that the first light distribution pattern 201formed by scanning of light from some light source unit 30 a of theplurality of light source units 30 and the second light distributionpattern 203 formed by scanning of light from other some light sourceunit 30 b of the plurality of light source units 30 partially overlapeach other in the up-down direction of the vehicle 100. When the signalindicating that the retroreflective object located in front of thevehicle 100 is detected is input from the detection device 110, thecontrol unit 60 controls the plurality of light source units 30 suchthat the light amount of light emitted to the predetermined region ARoverlapping the retroreflective object in the second light distributionpattern 203, which is one of the first light distribution pattern 201and the second light distribution pattern 203, is reduced as comparedwith the case where the signal indicating that the retroreflectiveobject is not detected is input from the detection device 110.

In a case where the retroreflective object reflects the light, theintensity of reflected light from the retroreflective object to theself-vehicle tends to increase as the intensity of light from the lightsource units 30 to the retroreflective object increases. Here, a casewhere the signal indicating that the retroreflective object is detectedis input to the control unit 60 from the detection device 110 iscompared with the case where the signal indicating that theretroreflective object is not detected is input to the control unit 60from the detection device 110. When the signal indicating that theretroreflective object is detected is input to the control unit 60, ascompared with the case where the signal indicating that theretroreflective object is not detected is input to the control unit 60,the light amount of light emitted to the predetermined region ARoverlapping the retroreflective object in the second light distributionpattern 203, which is one of the first light distribution pattern 201and the second light distribution pattern 203, is reduced. The light isa part of the light forming the second light distribution pattern 203.When the light amount of light decreases, the intensity of light to theretroreflective object is suppressed, and the intensity of the reflectedlight from the retroreflective object can be suppressed, as comparedwith the case where the light amount does not decrease. Thus, even whenthe reflected light travels to the self-vehicle, impartment of glare tothe driver of the self-vehicle can be suppressed. Accordingly, with thevehicle headlight 10, a reduction in driver's visibility can besuppressed.

Note that the vehicle headlight 10 of the present embodiment may furtherinclude the determination unit 50 that determines whether theretroreflective object satisfies the predetermined requirement that thelight amount of light reflected from the retroreflective object is equalto or more than the predetermined value in a case where the signalindicating the state of the retroreflective object is input from thedetection device 110, and the control unit 60 may control the pluralityof light source units 30 such that the light amount of light emitted tothe predetermined region AR overlapping the retroreflective object inthe second light distribution pattern 203, which is one of the firstlight distribution pattern 201 and the second light distribution pattern203, is reduced in a case where the determination unit 50 determinesthat the retroreflective object satisfies the predetermined requirementas compared with the case where the determination unit 50 determinesthat the retroreflective object does not satisfy the predeterminedrequirement. Also in this case, as described above, the intensity oflight to the retroreflective object is suppressed, and the intensity oflight reflected from the retroreflective object can be suppressed. Thus,even when the reflected light travels to the self-vehicle, impartment ofglare to the driver of the self-vehicle can be suppressed. Accordingly,with the vehicle headlight 10, a reduction in driver's visibility can besuppressed.

In addition, in the vehicle headlight 10 of the present embodiment, thelight source unit 30 b that emits light emitted to the predeterminedregion AR among the plurality of light source units 30 includes theplurality of light emitting elements 35. The control unit 60 controlsthe light source unit 30 b such that each of the light amount of lightfrom some light emitting element 35-6 of the plurality of light emittingelements 35 and the light amount of light from other some light emittingelement 35-7 of the plurality of light emitting elements 35 is reducedin a case where the determination unit 50 determines that theretroreflective object satisfies the predetermined requirement ascompared with the case where the determination unit 50 determines thatthe retroreflective object does not satisfy the predeterminedrequirement.

With the vehicle headlight 10, in the state in which the retroreflectiveobject satisfies the predetermined requirement, the irradiation of theretroreflective object with light is suppressed, and the intensity ofthe reflected light can be further suppressed as compared with the statein which the retroreflective object does not satisfy the predeterminedrequirement. Accordingly, with the vehicle headlight 10, a reduction indriver's visibility can be further suppressed.

In addition, in the vehicle headlight 10 of the present embodiment, thecontrol unit 60 may control the light source unit 30 such that the lightamount of light from some light emitting element 35-6 of the pluralityof light emitting elements 35 is reduced and the light amount of lightfrom other some light emitting element 35-7 of the plurality of lightemitting elements 35 is the same in a case where the determination unit50 determines that the retroreflective object satisfies thepredetermined requirement as compared with the case where thedetermination unit 50 determines that the retroreflective object doesnot satisfy the predetermined requirement.

In a case where the retroreflective object satisfies the predeterminedrequirement and a case where the retroreflective object does not satisfythe predetermined requirement, when the light amount of light from othersome light emitting element 35-7 is the same, the control unit 60 canperform the same control on the light emitting element 35-7 in bothcases. For example, even when the state is switched from the case wherethe retroreflective object does not satisfy the predeterminedrequirement to the case where the retroreflective object satisfies thepredetermined requirement, the control unit 60 may not need to changethe amount of power supplied to the light emitting element 35-7.Accordingly, the control unit 60 can easily control the light emittingelement 35-7 as compared with the case where the light amount of lightfrom the light emitting element 35-7 changes in a case where theretroreflective object satisfies the predetermined requirement and acase where the retroreflective object does not satisfy the predeterminedrequirement.

Although the present invention has been described above by taking theaforementioned embodiments as an example, the present invention is notlimited thereto.

In each of the above embodiments, the flowchart including Steps S1 to S5has been described as an example, but the flowchart is not particularlylimited.

The number of reflection blades 39 a is not particularly limited.

It is sufficient if the reflector 39 repeats the periodic motion toreflect the light from the plurality of light source units 30 toward theprojection lens 43 side, and scans the light in the left-right directionof the vehicle 100. The reflector 39 may be, for example, a mirror thatis swingable about an axis parallel to the reflecting surface. Inaddition, for example, the reflector 39 may be a micro electromechanical system (MEMS) mirror, and the drive unit 41 may be aresonator that is an actuator.

It is sufficient if the light source unit 30 of each embodiment isconfigured to emit light toward the reflector 39. In addition, similarlyto the light source unit 30 of the first embodiment, the light sourceunit 30 of the second embodiment may further include at least one lightemitting element different from the plurality of light emitting elementsarranged in a row along the predetermined direction. In this case, theplurality of light emitting elements in the light source unit may bearranged side by side so as to form two or more rows in thepredetermined direction.

In the light source unit 30 b of the second embodiment, the lightemitted from the light emitting element 35-6 may be the second light,and the light emitted from the light emitting element 35-7 may be thefirst light.

In the case of the configuration in which the light source unit 30 bincludes only one light emitting element, in a case where thedetermination unit 50 determines that the retroreflective objectsatisfies the predetermined requirement, it is sufficient if the controlunit 60 controls the light source unit 30 b such that the light amountof light from the one light emitting element 35 is reduced as comparedwith the case where the determination unit 50 determines that theretroreflective object does not satisfy the predetermined requirement.

In Step S5 of the second embodiment, the control unit 60 may control thelight source unit 30 b such that the light amount of light emitted fromthe light emitting elements 35-6 and 35-7 corresponding to thecondensing spots SC6 and SC7 becomes zero during a period in which thecondensing spots SC6 and SC7 pass through the non-irradiation region211. Alternatively, the control unit 60 may control the light sourceunit 30 b such that the light amount of light emitted from one of thelight emitting element 35-6 and the light emitting element 35-7 becomeszero and the light amount of light emitted from the other of the lightemitting element 35-6 and the light emitting element 35-7 becomes thesecond predetermined value other than zero.

In Step S5 of the second embodiment, in a case where the distancebetween the retroreflective object and the vehicle 100 is less than thepredetermined distance, it is sufficient if the sum of the light amountsof light emitted to the predetermined region AR overlapping theretroreflective object in the second light distribution pattern 203 maybe reduced as compared with the case where the distance between theretroreflective object and the vehicle 100 is equal to or more than thepredetermined distance. When the sum of the light amounts decreases, forexample, the control unit 60 may control the light source unit 30 b suchthat the light amount of light emitted from one of the light emittingelement 35-6 and the light emitting element 35-7 becomes the secondpredetermined value and the light amount of light emitted from the otherof the light emitting element 35-6 and the light emitting element 35-7becomes a predetermined value larger than the first predetermined value.Alternatively, the control unit 60 may control the light source unit 30b such that the light amount of light emitted from one of the lightemitting element 35-6 and the light emitting element 35-7 becomes thesecond predetermined value and the light amount of light emitted fromthe other of the light emitting element 35-6 and the light emittingelement 35-7 becomes the third predetermined value smaller than thesecond predetermined value.

In Step S5 of the second embodiment, the control unit 60 does not needto control the light emitting elements 35-6 and 35-7 such that the lightamounts of light emitted from the light emitting elements 35-6 and 35-7always become the second predetermined value during the light scanningperiod. For example, the control unit may control the light emittingelements 35-6 and 35-7 such that the light amount always becomes thesecond predetermined value in a certain scanning period of the scanningperiod. Alternatively, the control unit 60 may control the lightemitting elements 35-6 and 35-7 such that the light amount alwaysbecomes the second predetermined value in a certain predeterminedscanning period of the scanning period.

In addition, in Step S5 of the second embodiment, the control unit 60may control the light source unit 30 a such that the light amounts oflight emitted from the light emitting elements 35-1 to 35-5 become thesecond predetermined value. Alternatively, the control unit 60 maycontrol the light source unit 30 a such that the light amount of lightemitted from the light emitting elements 35-1 to 35-5 becomes apredetermined value larger than the first predetermined value. In thiscase, for example, the first predetermined value is 80% of the maximumvalue of the light amount, and the predetermined value larger than thefirst predetermined value is the maximum value of the light amount.

In the second embodiment, the control unit 60 detects the predeterminedregion AR where the retroreflective object overlaps in the second lightdistribution pattern 203 on the basis of the information from thedetection device 110 and sets the predetermined region AR as thenon-irradiation region 211, but does not need to be limited thereto. Forexample, the control unit 60 may detect the predetermined region ARwhere the face of a human overlaps in the second light distributionpattern 203 on the basis of the information from the detection device110, and may set the predetermined region AR as the non-irradiationregion 211.

In the second embodiment, it is described that the predetermined regionAR overlaps the second light distribution pattern 203, but even when thepredetermined region AR overlaps the first light distribution pattern201, it is sufficient if the control unit 60 controls the light sourceunit 30 b similarly to the case where the predetermined region ARoverlaps the second light distribution pattern 203.

The configuration of the lighting tool 20 a is the same as theconfiguration of the lighting tool 20 b, but may be different from theconfiguration of the lighting tool 20 b.

It is sufficient if the captured image is at least one of a moving imageand a still image.

The detection device 110 detects the presence of the target object, thepresence position of the target object, the type of the target object,or the like from the captured image captured by the camera, but does notneed to be limited thereto. In a case where a millimeter-wave radar, aLiDAR, or the like capable of detecting a target object is mounted, thedetection device 110 may detect the presence of the target object, thepresence position of the target object, the type of the target object,or the like on the basis of a signal input from the millimeter-waveradar, the LiDAR, or the like. In addition, the detection device 110 maydetect them on the basis of the captured image captured by the cameraand the signal input from the millimeter-wave radar, the LiDAR, or thelike. In addition, the calculation unit may calculate the distancebetween the retroreflective object and the vehicle 100 on the basis ofthe signal input from the millimeter-wave radar or the like. Inaddition, the detection device 110 may not identify or detect theretroreflective object and the human as a target object, and may detectone of the retroreflective object and the human. In addition, the signalindicating the retroreflective object or the human as a target objectmay be input to the control unit 60 from a configuration different fromthe determination unit 50, for example, the detection device 110.

In addition, the millimeter-wave radar transmits a millimeter wave to atarget object and receives a reflected wave that has hit and beenreflected from the target object. The millimeter-wave radar outputs asignal indicating a reception result to the calculation unit. Thereception result may be included in the state of the target object. Thecalculation unit may calculate the distance between the vehicle 100 andthe target object on the basis of the reception result input from themillimeter-wave radar.

In addition, the detection device 110 may include a stereo camera thatcaptures an image of the front of the vehicle 100. The stereo cameraincludes two cameras, and outputs captured images captured by therespective cameras to the calculation unit. The captured image may beincluded in the state of the target object. The calculation unit maycalculate the distance between the vehicle 100 and the target object onthe basis of stereo matching for obtaining parallax in correspondingpixels that are pixels corresponding to each other in the two capturedimages. Accordingly, the calculation unit calculates the distancebetween the vehicle 100 and the target object on the basis of thecaptured images from the stereo camera.

In addition, the detection unit of the detection device 110 may detect atemporal change amount of the size of the target object in the capturedimage from the captured image on which the image processing is performedby the image processing unit. The change amount is included in thesignal indicating the state of the target object. The change amount ofthe size of the retroreflective object 401 is smaller when the vehicle100 away from the target object approaches the target object after alapse of time, and the change amount of the size of the target object islarger when the vehicle moves forward and the vehicle 100 closer to thetarget object further approaches the target object after a lapse oftime. The size of the target object indicates, for example, the area ofthe target object, the width of the target object, and the like. Whendetecting a target object located in front of the vehicle 100, thedetection device 110 outputs a signal indicating the state of the targetobject such as the ratio of the target object in the captured image andthe change amount to the calculation unit. The calculation unit maycalculate the distance on the basis of the ratio and the change amount.

In addition, when the distance between, for example, the retroreflectiveobject 401, which is a target object, and the vehicle 100 is less thanthe predetermined distance in a state where the light amount of lightemitted from the pair of lighting tools 20 does not change, theintensity of the reflected light from the retroreflective object 401 tothe self-vehicle tends to increase as compared with the state where thedistance is equal to or more than the predetermined distance. By theway, in the vehicle headlight 10 of the present embodiment, the statethat satisfies the predetermined requirement is a state in which thedistance between, for example, the retroreflective object 401, which isa target object, and the vehicle 100 is less than the predetermineddistance. In a case where the distance is less than the predetermineddistance, the control unit 60 controls the pair of lighting tools 20 asdescribed in the first embodiment or the second embodiment. Accordingly,when the distance is less than the predetermined distance, the intensityof the reflected light traveling from the retroreflective object 401 tothe self-vehicle can be suppressed, the impartment of glare can besuppressed, and the reduction in driver's visibility can be suppressed,as compared with the state where the distance is equal to or more thanthe predetermined distance.

The predetermined requirement is not particularly limited, and may be anapparent size of the target object described above or the like insteadof the distance. In a case where the predetermined requirement is theapparent size of the target object, the state that satisfies thepredetermined requirement indicates a state in which the apparent sizeof the target object is equal to or more than a predetermined value. Inthis case, the detection unit of the detection device 110 detects thesize of the target object in the captured image from the captured imageon which the image processing is performed by the image processing unitas described above. The determination unit 50 determines whether thetarget object satisfies the predetermined requirement on the basis ofthe size of the target object. The predetermined value is recorded inthe recording unit 70 as a threshold value, and may be changed accordingto the traveling status of the vehicle 100 such as daytime andnighttime. Even when the distance between the target object and thevehicle 100 is equal to or more than the predetermined distance, in acase where the apparent size of the target object is equal to or morethan the predetermined value, there is a concern that a part of thelight from the vehicle 100 travels from the target object to the vehicle100 as reflected light and gives glare to the driver of the self-vehicleas compared with the case where the apparent size of the target objectis less than the predetermined value. As described above, in a casewhere the state that satisfies the predetermined requirement is a statein which the apparent size of the target object is equal to or more thanthe predetermined value, the control unit 60 controls the pair oflighting tools 20 as described above. Accordingly, even in a case wherethe distance between the target object and the vehicle 100 is equal toor more than the predetermined distance and the apparent size of thetarget object is equal to or more than the predetermined value, theintensity of the reflected light traveling from the target object to theself-vehicle can be suppressed, the impartment of glare can besuppressed, and the reduction in driver's visibility can be suppressed.In the above description, the apparent size of the target object hasbeen described, but the predetermined requirement may be the ratio ofthe target object in the captured image. In a case where thepredetermined requirement is the ratio, the state that satisfies thepredetermined requirement is a state in which the ratio is equal to ormore than the predetermined value.

In the above description, the state that satisfies the predeterminedrequirement is a state in which the apparent size of the target objectis equal to or more than the predetermined value, but does not need tobe limited thereto. For example, the state that satisfies thepredetermined requirement may be a state in which any one of the statein which the distance between the target object and the vehicle 100 isless than the predetermined distance, the state in which the apparentsize of the target object is equal to or more than the predeterminedvalue, and the state in which the ratio is equal to or more than thepredetermined value described in the embodiments is combined.

The configuration of the detection device 110 may be included in theconfiguration of the vehicle headlight 10. In this case, the camera ofthe detection device 110 may be arranged inside the enclosure of thelighting tool 20.

When the retroreflective object no longer satisfies the predeterminedrequirement, the control unit 60 may set the region where theretroreflective object is no longer detected as the light amountnon-change region 313 or the irradiation region 213.

As described above, according to the first embodiment of the presentinvention, the vehicle headlight that enables easy driving is provided,and the vehicle headlight can be used in the field of vehicle headlightssuch as of automobiles. In addition, according to the second embodimentof the present invention, the vehicle headlight capable of suppressing areduction in driver's visibility is provided, and the vehicle headlightcan be used in the field of vehicle headlights such as of automobiles.

1. A vehicle headlight comprising: a light source unit configured toinclude a plurality of light emitting elements; a reflector configuredto repeat a periodic motion to reflect light from the plurality of lightemitting elements and scan the light to form a predetermined lightdistribution pattern; and a control unit configured to control the lightsource unit, wherein the predetermined light distribution patternincludes a superimposition region where light from at least two of thelight emitting elements is superimposed on each other, and in a casewhere a signal indicating that a target object located in front of avehicle is detected is input from a detection device, the control unitcontrols the light source unit such that a light amount of light emittedfrom some light emitting elements to a predetermined region overlappingthe target object does not change and a light amount of light emittedfrom other some light emitting element to the predetermined regionoverlapping the target object changes among the light emitting elementsthat emit light to the predetermined region overlapping the targetobject in the superimposition region.
 2. The vehicle headlight accordingto claim 1, wherein a width of the predetermined region in a left-rightdirection overlapping the target object changes according to a distancebetween the vehicle and the target object.
 3. The vehicle headlightaccording to claim 1, wherein in a case where the target object is ahuman, the control unit controls the light source unit such that thelight amount of light emitted from the other some light emittingelements to the predetermined region overlapping the target objectincreases.
 4. The vehicle headlight according to claim 1, wherein in acase where the target object is a retroreflective object, the controlunit controls the light source unit such that the light amount of lightemitted from the other some light emitting elements to the predeterminedregion overlapping the target object decreases.
 5. The vehicle headlightaccording to claim 1, wherein the control unit controls the light sourceunit such that the light amount of light emitted from the other somelight emitting elements to the predetermined region overlapping thetarget object changes according to the distance between the vehicle andthe target object.
 6. The vehicle headlight according to claim 4,wherein the control unit controls the light source unit such that thelight amount of light emitted from the other some light emittingelements to the predetermined region overlapping the target objectdecreases according to intensity of light from the target object to thevehicle.
 7. The vehicle headlight according to claim 4, wherein thecontrol unit controls the light source unit such that the light amountof light emitted from the other some light emitting elements to thepredetermined region overlapping the target object decreases as an angleformed by a traveling direction of the vehicle and a direction from thevehicle toward the target object decreases.
 8. The vehicle headlightaccording to claim 5, wherein in a case where a number of the lightemitting elements that emit light to the predetermined regionoverlapping the target object is three or more, the control unit changesthe number of the other some light emitting elements to change the lightamount of light emitted from the other some light emitting elements tothe predetermined region overlapping the target object.
 9. The vehicleheadlight according to claim 1, wherein the reflector is a rotaryreflector that reflects light from the plurality of light emittingelements while rotating.
 10. The vehicle headlight according to claim 1,further comprising: a determination unit that determines whether or notthe target object satisfies a predetermined requirement that the lightamount of reflected light from the target object is equal to or morethan a predetermined value in a case where a signal indicating a stateof the target object is input from the detection device, wherein eachscanning region through which a spot of light from each light emittingelement scanned by the reflector in the predetermined light distributionpattern passes is divided into a pair of end portions that includes anend in a scanning direction and is equal to or larger than a width ofthe spot in the scanning direction and a center portion sandwiched bythe pair of end portions, each of the scanning regions is arranged to bedisplaced in the scanning direction, a part of the center portion ofeach of the scanning regions overlaps a part of center portions of allthe other scanning regions, and the end portion of each of the scanningregions does not overlap the end portion of all the other scanningregions, in a case where the predetermined region moves in the scanningdirection from a first state in which the predetermined region islocated in the center portion in all the scanning regions correspondingto the other some light emitting elements to a second state in which thepredetermined region overlaps the end portion in at least one of thescanning regions corresponding to the other some light emitting elementsand is located in the center portion in the scanning regioncorresponding to at least one of the light emitting elements among thesome light emitting elements, the control unit controls the light sourceunit such that the light amount emitted to the predetermined region fromthe light emitting element corresponding to the scanning region in whichthe predetermined region overlaps the end portion in the other somelight emitting elements returns to the light amount emitted to thepredetermined region in a case where the determination unit does notdetermine that the target object satisfies the predeterminedrequirement, and the light amount emitted to the predetermined region inthe second state becomes the light amount in the first state by changingthe light amount emitted to the predetermined region from at least oneof the light emitting elements corresponding to the scanning region inwhich the predetermined region is located in the center portion amongsome light emitting elements.
 11. The vehicle headlight according toclaim 10, wherein the predetermined region in the second state islocated in the center portion of the scanning region corresponding totwo or more of the light emitting elements among the some light emittingelements, and in a case of changing from the first state to the secondstate, the light amount emitted to the predetermined region from thelight emitting element corresponding to the scanning region in which adistance between a center of the center portion in the scanningdirection and the predetermined region is shortest among the two or moreof the light emitting elements among the some light emitting elementschanges.
 12. The vehicle headlight according to claim 10, wherein astate that satisfies the predetermined requirement is a state in whichthe distance between the target object and the vehicle is less than apredetermined distance.
 13. The vehicle headlight according to claim 10,wherein a state that satisfies the predetermined requirement is a statein which an apparent size of the target object is equal to or more thana predetermined value.
 14. A vehicle headlight comprising: a pluralityof light source units; a reflector configured to repeat a periodicmotion to reflect light from the plurality of light source units andscan the light; and a control unit configured to control the pluralityof light source units, wherein the reflector reflects the light from theplurality of light source units such that a first light distributionpattern formed by scanning of light from some light source units amongthe plurality of light source units and a second light distributionpattern formed by scanning of light from other some light source unitsamong the plurality of light source units partially overlap each otherin an up-down direction of a vehicle, and in a case where a signalindicating that a retroreflective object located in front of the vehicleis detected is input from a detection device, the control unit controlsthe plurality of light source units such that a light amount of lightemitted to a predetermined region overlapping the retroreflective objectin one of the first light distribution pattern and the second lightdistribution pattern is reduced as compared with a case where a signalindicating that the retroreflective object is not detected is input fromthe detection device.
 15. The vehicle headlight according to claim 14,further comprising: a determination unit that determines whether or notthe retroreflective object satisfies a predetermined requirement thatthe light amount of reflected light from the retroreflective object isequal to or more than a predetermined value in a case where a signalindicating a state of the retroreflective object is input from thedetection device, wherein the light source unit that emits the lightemitted to the predetermined region includes a plurality of lightemitting elements, and the control unit controls the light source unitsuch that each of the light amount of the light from some light emittingelements among the plurality of light emitting elements and the lightamount of the light from other some light emitting elements among theplurality of light emitting elements is reduced in a case where thedetermination unit determines that the retroreflective object satisfiesthe predetermined requirement as compared with a case where thedetermination unit determines that the retroreflective object does notsatisfy the predetermined requirement.
 16. The vehicle headlightaccording to claim 14, further comprising: a determination unit thatdetermines whether the retroreflective object satisfies a predeterminedrequirement that the light amount of light reflected from theretroreflective object is equal to or more than a predetermined value ina case where a signal indicating a state of the retroreflective objectis input from the detection device, wherein the light source unit thatemits the light emitted to the predetermined region includes a pluralityof light emitting elements, and the control unit controls the lightsource unit such that the light amount of the light from some lightemitting elements among the plurality of light emitting elements isreduced and the light amount of the light from other some light emittingelements among the plurality of light emitting elements becomes same ina case where the determination unit determines that the retroreflectiveobject satisfies the predetermined requirement as compared with a casewhere the determination unit determines that the retroreflective objectdoes not satisfy the predetermined requirement.
 17. The vehicleheadlight according to claim 15, wherein a state that satisfies thepredetermined requirement is a state in which a distance between theretroreflective object and the vehicle is less than a predetermineddistance.
 18. The vehicle headlight according to claim 15, wherein astate that satisfies the predetermined requirement is a state in whichan apparent size of the retroreflective object is equal to or more thana predetermined value.